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“Farmers' decision to use drought early warning system in developing countries”. Sharafi L, Zarafshani K, Keshavarz M, Azadi H, Van Passel S, Science Of The Total Environment 758, 142761 (2021). http://doi.org/10.1016/J.SCITOTENV.2020.142761
Abstract: Drought is a persistent, sluggish natural disaster in developing countries that has generated a financial burden and an unstable climate. Farmers should adopt early warning systems (EWS) in their strategies for monitoring drought to reduce its serious consequences. However, farmers in developing countries are reluctant to use EWS as their management strategies. Hence, the aim of this study was to investigate the decision of farmers to use climate knowledge through the model of farming activity in Kermanshah Township, Iran. A surveyor questionnaire was used to gather data from 370 wheat farmers using random sampling methods inmulti-stage clusters. Results revealed that the decision to use climate information is affected by personal factors, attitude towards climate information, objectives of using climate information, and external/physical farming factors. The result of this study has implications for drought management practitioners. To be specific, the results can aid policymakers to design early alert programs to minimize the risk of drought and thus move from conventional to climate smart agriculture. (C) 2020 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1016/J.SCITOTENV.2020.142761
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“Environmental impact assessment and efficiency of cotton : the case of Northeast Iran”. Naderi Mahdei K, Esfahani SMJ, Lebailly P, Dogot T, Van Passel S, Azadi H, Environment, development and sustainability , 1 (2022). http://doi.org/10.1007/S10668-022-02490-5
Abstract: Cotton is one of the important crops that play an important role in creating a livelihood for rural people in many parts of Iran. Cotton production necessitates a large amount of resources (e.g., fossil energy and agrochemicals, all of which have the potential to damage the environment in various ways). The purpose of the current study was to evaluate the environmental effects of cotton production in the South Khorasan Province of Iran. For this purpose, life cycle assessment (LCA) and data envelopment analysis (DEA) techniques have been applied to investigate the environmental impacts of cotton production. LCA is a practical method to evaluate the environment on the product flow, in which all aspects of the product life cycle are examined by a comprehensive approach. Furthermore, combining the LCA method with other managerial strategies such as DEA could allow researchers to provide decision-makers with more practical and interpretable data. The findings of the efficiency test showed that the average technical efficiency, pure technical efficiency, and scale efficiency were 0.81, 0.92, and 0.87, respectively. Respiratory inorganics (i.e., respiratory effects resulting from winter smog caused by emissions of dust, sulfur, and nitrogen oxides to air) posed the greatest environmental burden in cotton production, followed by non-renewable energy, carcinogens, and global warming. In addition, the highest effects were on human health, and then, on resources and climate change. Energy, on-system pollution, and waste played a crucial role in the environmental impacts of cotton processing. This study suggests improving farmers' knowledge toward the optimum application of chemical fertilizers, or their substitution with green fertilizers, which reduces the environmental effect of growing cotton in the area.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1007/S10668-022-02490-5
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“A systematic comparison of commercially produced struvite : quantities, qualities and soil-maize phosphorus availability”. Muys M, Phukan R, Brader G, Samad A, Moretti M, Haiden B, Pluchon S, Roest K, Vlaeminck SE, Spiller M, Science Of The Total Environment 756, 143726 (2021). http://doi.org/10.1016/J.SCITOTENV.2020.143726
Abstract: Production of struvite (MgNH4PO4·6H2O) from waste streams is increasingly implemented to recover phosphorus (P), which is listed as a critical raw material in the European Union (EU). To facilitate EU-wide trade of P-containing secondary raw materials such as struvite, the EU issued a revised fertilizer regulation in 2019. A comprehensive overview of the supply of struvite and its quality is presently missing. This study aimed: i) to determine the current EU struvite production volumes, ii) to evaluate all legislated physicochemical characteristics and pathogen content of European struvite against newly set regulatory limits, and iii) to compare not-regulated struvite characteristics. It is estimated that in 2020, between 990 and 1250 ton P are recovered as struvite in the EU. Struvite from 24 European production plants, accounting for 30% of the 80 struvite installations worldwide was sampled. Three samples failed the physicochemical legal limits; one had a P content of <7% and three exceeded the organic carbon content of 3% dry weight (DW). Mineralogical analysis revealed that six samples had a struvite content of 80–90% DW, and 13 samples a content of >90% DW. All samples showed a heavy metal content below the legal limits. Microbiological analyses indicated that struvite may exceed certain legal limits. Differences in morphology and particle size distribution were observed for struvite sourced from digestate (rod shaped; transparent; 82 mass% < 1 mm), dewatering liquor (spherical; opaque; 65 mass% 1–2 mm) and effluent from upflow anaerobic sludge blanket reactor processing potato wastewater (spherical; opaque; 51 mass% < 1 mm and 34 mass% > 2 mm). A uniform soil-plant P-availability pattern of 3.5–6.5 mg P/L soil/d over a 28 days sampling period was observed. No differences for plant biomass yield were observed. In conclusion, the results highlight the suitability of most struvite to enter the EU fertilizer market.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1016/J.SCITOTENV.2020.143726
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“Hierarchical zeolites containing embedded Cd0.2Zn0.8S as a photocatalyst for hydrogen production from seawater”. Yuan Y, Wu F-J, Xiao S-T, Wang Y-T, Yin Z-W, Van Tendeloo G, Chang G-G, Tian G, Hu Z-Y, Wu S-M, Yang X-Y, Chemical communications 59, 7275 (2023). http://doi.org/10.1039/D3CC01409F
Abstract: Uncovering an efficient and stable photocatalytic system for seawater splitting is a highly desirable but challenging goal. Herein, Cd0.2Zn0.8S@Silicalite-1 (CZS@S-1) composites, in which CZS is embedded in the hierarchical zeolite S-1, were prepared and show remarkably high activity, stability and salt resistance in seawater.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.9
DOI: 10.1039/D3CC01409F
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“A real-world analysis on the efficacy and tolerability of liposomal irinotecan plus 5-fluorouracil and folinic acid in metastatic pancreatic ductal adenocarcinoma in Belgium”. Verbruggen L, Verheggen L, Vanhoutte G, Loly C, Lybaert W, Borbath I, Vergauwe P, Hendrickx K, Debeuckelaere C, de Haar-Holleman A, Van Laethem J-L, Peeters M, Therapeutic advances in medical oncology 15, 1 (2023). http://doi.org/10.1177/17588359231181500
Abstract: Background: Currently, nanoliposomal irinotecan (nal-IRI) + 5-fluorouracil/folinic acid (5-FU/ LV) is the only approved second-line treatment for patients suffering from metastatic pancreatic ductal adenocarcinoma (mPDAC). However, also other chemotherapeutic regimens are used in this setting and due to the lack of clear real-world data on the efficacy of the different regimens, there is no consensus on the optimal treatment sequence for mPDAC patients. Objectives: To provide information on the safe and efficacious use of nal-IRI + 5-FU/LV in clinical practice in Belgium, which is needed for healthcare professionals to estimate the risk-benefit ratio of the intervention. Methods: Medical data of adult patients with mPDAC who were treated with nal-IRI + 5-FU/ LV in one of the participating Belgian hospitals were retrospectively collected. Kaplan-Meier analysis was performed to obtain survival curves to estimate the median overall survival (OS) and progression-free survival (PFS). All other results were presented descriptively. Results: A total of 56 patients [median age at diagnosis: 69 years (range 43 years), 57.1% male] were included. Patients received a median of 5 (range 49 cycles) nal-IRI + 5-FU/LV cycles, extended over 10 weeks (range 130.8 weeks). The median start dose for nal-IRI was 70 mg/ m(2) (range 49.24 mg/m(2)) and chemotherapy dose reduction and delay occurred in, respectively, 42.8% and 37.5% of the patients. The median OS was 6.8 months (95% CI: 5.6-8.4 months) with a 6-month survival rate of 57.4% and a 1-year survival rate of 27.8% in the overall study population. The median OS for patients treated with nal-IRI as second-line therapy or as laterline treatment was, respectively, 6.8 months (95% CI: 5.9-7.0 months) and 5.6 months (95% CI: 4.2-no upper limit). In the overall study population, a median PFS of 3.1 months (95% CI: 2.4-4.6 months) and a disease control rate of 48.3%, comprising 30.4% stable disease, 16.1% partial and 1.8% complete response, was observed. The median PFS for patients treated with nal-IRI as second-line therapy was 3.9 months (95% CI: 2.8-4.8 months) while this was 2.4 months (95% CI: 1.9-9.1 months) for those that received nal-IRI in a later-line treatment. In terms of safety, gastrointestinal problems occurred most (64.3% of the patients) and from all reported treatment emergent adverse events, 39.2% were grade 3 or 4. Conclusion: Nal-IRI + 5-FU/LV is a valuable, effective, and safe sequential treatment option following gemcitabine-based therapy in patients with mPDAC.
Keywords: A1 Journal article; Center for Oncological Research (CORE)
Impact Factor: 4.9
DOI: 10.1177/17588359231181500
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“Consistent predictors of microbial community composition across spatial scales in grasslands reveal low context‐dependency”. Radujković, D, Vicca S, van Rooyen M, Wilfahrt P, Brown L, Jentsch A, Reinhart KO, Brown C, De Gruyter J, Jurasinski G, Askarizadeh D, Bartha S, Beck R, Blenkinsopp T, Cahill J, Campetella G, Canullo R, Chelli S, Enrico L, Fraser L, Hao X, Henry HAL, Hohn M, Jouri MH, Koch M, Lawrence Lodge R, Li FY, Lord JM, Milligan P, Minggagud H, Palmer T, Schröder B, Szabó, G, Zhang T, Zimmermann Z, Verbruggen E, Molecular ecology 32, 6924 (2023). http://doi.org/10.1111/MEC.17178
Abstract: Environmental circumstances shaping soil microbial communities have been studied extensively. However, due to disparate study designs, it has been difficult to resolve whether a globally consistent set of predictors exists, or context‐dependency prevails. Here, we used a network of 18 grassland sites (11 of those containing regional plant productivity gradients) to examine (i) if similar abiotic or biotic factors predict both large‐scale (across sites) and regional‐scale (within sites) patterns in bacterial and fungal community composition, and (ii) if microbial community composition differs consistently at two levels of regional plant productivity (low vs. high). Our results revealed that bacteria were associated with particular soil properties (such as base saturation) and both bacteria and fungi were associated with plant community composition across sites and within the majority of sites. Moreover, a discernible microbial community signal emerged, clearly distinguishing high and low‐productivity soils across different grasslands independent of their location in the world. Hence, regional productivity differences may be typified by characteristic soil microbial communities across the grassland biome. These results could encourage future research aiming to predict the general effects of global changes on soil microbial community composition in grasslands and to discriminate fertile from infertile systems using generally applicable microbial indicators.
Keywords: A1 Journal article; Plant and Ecosystems (PLECO) – Ecology in a time of change
Impact Factor: 4.9
DOI: 10.1111/MEC.17178
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“Farmers' preferences and willingness to pay for improved irrigation water supply program : a discrete choice experiment”. Chekol Zewdie M, Moretti M, Tenessa DB, Van Passel S, Environment, development and sustainability , 1 (2023). http://doi.org/10.1007/S10668-023-03759-Z
Abstract: This study examines smallholder farmers' preferences and willingness to pay for an improved irrigation water supply program in northwest Ethiopia. We employed a discrete choice experiment with five attributes and three levels. Data were collected from randomly selected sample households of both irrigation users and non-users. A total of 379 respondents participated, and a mixed logit model was used to analyze the household-level survey data. The result indicates that to deviate from the business-as-usual scenario, smallholder farmers are willing to pay between 3,228 and 8,327 Ethiopian Birr per hectare of irrigated land. Furthermore, the results showed a strong public preference for access to produce cash crops, followed by irrigation water availability in the dry season, and adequate access to improved farm inputs. The results also provide useful information for policymakers and suggested possibilities for generating finance from farmers to cover the operation and maintenance costs of irrigation schemes. Also, this study result reveals that irrigation development and expansion must be integrated into a comprehensive support package that combines irrigation water with access to improved farm inputs and access to produce cash crops on farmers' farm plots.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1007/S10668-023-03759-Z
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“Undoing the development army : a paradigm shift from transfer of technology to agricultural innovation system in Ethiopian extension”. Gebremariam YA, Dessein J, Wondimagegnhu BA, Breusers M, Lenaerts L, Adgo E, Van Passel S, Minale AS, Nyssen J, Environment, development and sustainability , 1 (2023). http://doi.org/10.1007/S10668-023-04136-6
Abstract: Appropriate use of agricultural technologies and diversifying the farming activities is critical to addressing food security problems in Africa, including Ethiopia. The country is experimenting with the new Agricultural Innovation System (AIS) approach alongside the well-established Transfer of Technology (ToT) approach. This paper analyzes the gaps between policy discourses (as reflected in policy documents and strategic orientation documents) and extension practices (as reflected in the daily exchanges between farmers and the frontline staff of the Ethiopian extension system). It provides insights into the challenges faced and emphasizes the need for better coordination between policy formulation and implementation to enhance extension services. Policymakers, practitioners, and researchers can benefit from the valuable perspectives the findings offer. The study contributes to understanding the relationship between policy discourses and extension practices, and its implications can inform policy design and implementation in similar contexts. A qualitative research approach was deployed to analyze policy discourse and practice. Data were collected in Fogera, a district in Northwest Ethiopia, between August 2018 and February 2019. The data for the paper were obtained from 23 Focus Group Discussions conducted with men and women. 13 Informant Interviews (KIIs) were also carried out with personnel at different levels of government agricultural services and departments. Transcripts of recordings of the Focus Group Discussions (FGDs) and Key Informant Interviews (KIIs) were analyzed using a deductive approach. The study focuses on rice crops in the Fogera district, which are crucial for food security and reducing poverty. Although the geographic area is limited, the results can be used to improve the extension system in other areas facing similar challenges. Specifically, the study suggests switching from the traditional transfer of technology approach to the agricultural innovation system approach. Furthermore, the study's techniques, such as qualitative interviews, may have limitations and not fully capture the intricacies of policy and extension practices. The findings demonstrate that, although the policy documents strongly adhere to agricultural innovation system principles, top-down transfer of technology approaches continues to dominate in practice. Moreover, we have found potential discrepancies between the training content delivered and the specific needs of smallholder farmers. Practically, prescriptive systems are still used because agricultural innovation system approaches are not well understood by the Extension Agents. To realize a genuine agricultural innovation system, Ethiopia's extension apparatus should move forward with building committed and robust relationships between farmers, extension agents, researchers, private sectors, and non-governmental organizations. To this end, more research, enhanced training, and improved institutions are needed on what genuine agricultural innovation system could look like at the grass-roots level. This also includes understanding the roles that different actors within Ethiopia's development army should assume how a multi-actor policy dialogue can be organized.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1007/S10668-023-04136-6
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“Atomic structure of defects in anion-deficient perovskite-based ferrites with a crystallographic shear structure”. Batuk M, Turner S, Abakumov AM, Batuk D, Hadermann J, Van Tendeloo G, Inorganic chemistry 53, 2171 (2014). http://doi.org/10.1021/ic4028404
Abstract: Crystallographic shear (CS) planes provide a new structure-generation mechanism in the anion-deficient perovskites containing lone-pair cations. Pb2Sr2Bi2Fe6O16, a new n = 6 representative of the AnBnO3n2 homologous series of the perovskite-based ferrites with the CS structure, has been synthesized using the solid-state technique. The structure is built of perovskite blocks with a thickness of four FeO6 octahedra spaced by double columns of FeO5 edge-sharing distorted tetragonal pyramids, forming 1/2[110](101)p CS planes (space group Pnma, a = 5.6690(2) Å, b = 3.9108(1) Å, c = 32.643(1) Å). Pb2Sr2Bi2Fe6O16 features a wealth of microstructural phenomena caused by the flexibility of the CS planes due to the variable ratio and length of the constituting fragments with {101}p and {001}p orientation. This leads to the formation of waves, hairpins, Γ-shaped defects, and inclusions of the hitherto unknown layered anion-deficient perovskites Bi2(Sr,Pb)Fe3O8.5 and Bi3(Sr,Pb)Fe4O11.5. Using a combination of diffraction, imaging, and spectroscopic transmission electron microscopy techniques this complex microstructure was fully characterized, including direct determination of positions, chemical composition, and coordination number of individual atomic species. The complex defect structure makes these perovskites particularly similar to the CS structures in ReO3-type oxides. The flexibility of the CS planes appears to be a specific feature of the Sr-based system, related to the geometric match between the SrO perovskite layers and the {100}p segments of the CS planes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 6
DOI: 10.1021/ic4028404
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“Cation ordering and flexibility of the BO42- tetrahedra in incommensurately modulated CaEu2(BO4)4 (B = Mo, W) scheelites”. Abakumov AM, Morozov VA, Tsirlin AA, Verbeeck J, Hadermann J, Inorganic chemistry 53, 9407 (2014). http://doi.org/10.1021/ic5015412
Abstract: The factors mediating cation ordering in the scheelite-based molybdates and tungstates are discussed on the basis of the incommensurately modulated crystal structures of the CaEu2(BO4)(4) (B = Mo, W) red phosphors solved from high-resolution synchrotron powder X-ray diffraction data. Monoclinic CaEu2(WO4)(4) adopts a (3 + 1)-dimensionally modulated structure [superspace group I2/b(alpha beta 0)00, a = 5.238 73(1)A, b = 5.266 35(1) A, c = 11.463 19(9) A, gamma = 91.1511(2)degrees, q = 0.56153(6)a* + 0.7708(9)b*, R-F = 0.050, R-p = 0.069], whereas tetragonal CaEu2(MoO4)(4) is (3 + 2)-dimensionally modulated [superspace group I4(1)/ a(alpha beta 0)00(-beta alpha 0)00, a = 5.238 672(7) A, c = 11.548 43(2) A, q(1) = 035331(8)a* + 0.82068(9)b*, q(2) = -0.82068(9)a* + 0.55331(8)b*, R-F = 0.061, R-p = 0.082]. In both cases the modulation arises from the ordering of the Ca/Eu cations and the cation vacancies at the A-sublattice of the parent scheelite ABO(4) structure. The cation ordering is incomplete and better described with harmonic rather than with steplike occupational modulation functions. The structures respond to the variation of the effective charge and cation size at the A-position through the flexible geometry of the MoO42- and WO42- tetrahedra demonstrating an alternation of stretching the B-O bond lengths and bending the O-B-O bond angles. The tendency towards A-site cation ordering in scheelites is rationalized using the difference in ionic radii and concentration of the A-site vacancies as parameters and presented in the form of a structure map.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 48
DOI: 10.1021/ic5015412
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“Cationic clathrate of type-III Ge172-xPxTey (y\approx21,5, x\approx2y) : synthesis, crystal structure and thermoelectric properties”. Kirsanova MA, Mori T, Maruyama S, Abakumov AM, Van Tendeloo G, Olenev A, Shevelkov AV, Inorganic chemistry 52, 8272 (2013). http://doi.org/10.1021/ic401203r
Abstract: A first germanium-based cationic clathrate of type-III, Ge129.3P42.7Te21.53, was synthesized and structurally characterized (space group P42/mnm, a = 19.948(3) Å, c = 10.440(2) Å, Z = 1). In its crystal structure, germanium and phosphorus atoms form three types of polyhedral cages centered with Te atoms. The polyhedra share pentagonal and hexagonal faces to form a 3D framework. Despite the complexity of the crystal structure, the Ge129.3P42.7Te21.53 composition corresponds to the Zintl counting scheme with a good accuracy. Ge129.3P42.7Te21.53 demonstrates semiconducting/insulating behavior of electric resistivity, high positive Seebeck coefficient (500 μV K1 at 300 K), and low thermal conductivity (<0.92 W m1 K1) within the measured temperature range.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 3
DOI: 10.1021/ic401203r
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“Crystal structure and phase transitions in Sr3WO6”. King G, Abakumov AM, Hadermann J, Alekseeva AM, Rozova MG, Perkisas T, Woodward PM, Van Tendeloo G, Antipov EV, Inorganic chemistry 49, 6058 (2010). http://doi.org/10.1021/ic100598v
Abstract: The crystal structures of the beta and gamma polymorphs of Sr3WO6 and the gamma <->beta phase transition have been investigated using electron diffraction, synchrotron X-ray powder diffraction, and neutron powder diffraction. The gamma-Sr3WO6 polymorph is stable above T-c approximate to 470 K and adopts a monoclinically distorted double perovskite A(2)BB'O-6= Sr2SrWO6 structure (space group Cc, a = 10.2363(1)angstrom, b= 17.9007(1)angstrom, c= 11.9717(1)angstrom, beta=125.585(1)degrees at T= 1373 K, Z=12, corresponding to a = a(p)+1/2b(p) – 1/2c(p), b =3/2b(p) + 3/2c(p), c =-b(p) + c(p), a(p),b(p), c(p), lattice vectors of the parent Fm (3) over barm double perovskite structure). Upon cooling it undergoes a continuous phase transition into the triclinically distorted beta-Sr3WO6 phase (space group Cl, a = 10.09497(3)angstrom, b = 17.64748(5)angstrom, c = 11.81400(3)angstrom, alpha = 89.5470(2)degrees, beta= 125.4529(2)degrees, gamma =90.2889(2)degrees at T= 300 K). Both crystal structures of Sr3WO6 belong to a family of double perovskites with broken corner sharing connectivity of the octahedral framework. A remarkable feature of the gamma-Sr3WO6 structure is a non-cooperative rotation of the WO6 octahedra. One third of the WO6 octahedra are rotated by 45 about either the bp or the cp axis of the parent double perovskite structure. As a result, the WO6 octahedra do not share corners but instead share edges with the coordination polyhedra of the Sr cations at the B positions increasing their coordination number from 6 to 7 or 8. The crystal structure of the beta-phase is very close to the structure of the gamma-phase; decreasing symmetry upon the gamma ->beta transformation occurs because of unequal octahedral rotation angles about the bp and cp axes and increasing distortions of the WO6 octahedra.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 18
DOI: 10.1021/ic100598v
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“The crystal structure of \alpha-K3AIF6: elpasolites and double perovskites with broken corner-sharing connectivity of the octahedral framework”. Abakumov AM, King G, Laurinavichute VK, Rozova MG, Woodward PM, Antipov EV, Inorganic chemistry 48, 9336 (2009). http://doi.org/10.1021/ic9013043
Abstract: The crystal structure of α-K3AlF6 was solved and refined from a combination of powder X-ray and neutron diffraction data (a = 18.8385(3)Å, c = 33.9644(6)Å, S.G. I41/a, Z = 80, RP(X-ray) = 0.037, RP(neutron) = 0.053). The crystal structure is of the A2BB′X6 elpasolite type with the a = b ≈ ae√5, c = 4ae superstructure (ae, parameter of the elpasolite subcell) and rock-salt-type ordering of the K and Al cations over the B and B′ positions, respectively. The remarkable feature of α-K3AlF6 is a rotation of 2/5 of the AlF6 octahedra by π/4 around one of the crystal axes of the elpasolite subcell, coinciding with the 4-fold symmetry axes of the AlF6 octahedra. The rotation of the AlF6 octahedra replaces the corner-sharing between the K and Al polyhedra by edge-sharing, resulting in an increase of coordination numbers of the K cations at the B positions up to 7 and 8. Due to significant deformations of the K polyhedra, the corner-sharing connectivity of the octahedral elpasolite framework is broken and the rotations of the AlF6 octahedra do not have a cooperative character. Elpasolites and double perovskites with similar structural organization are discussed. The difference in ionic radii of the B and B′ cations as well as the tolerance factor are proposed to be the parameters governing the formation of elpasolites and double perovskites with broken corner-sharing connectivity of the octahedral framework.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 20
DOI: 10.1021/ic9013043
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“Effect of lone-electron-pair cations on the orientation of crystallographic shear planes in anion-deficient perovskites”. Batuk D, Batuk M, Abakumov AM, Tsirlin AA, McCammon CM, Dubrovinsky L, Hadermann J, Inorganic chemistry 52, 10009 (2013). http://doi.org/10.1021/ic4012845
Abstract: Factors affecting the structure and orientation of the crystallographic shear (CS) planes in anion-deficient perovskites are investigated using the (Pb1−zSrz)1−xFe1+xO3−y perovskites as a model system. The orientation of the CS planes in the system varies unevenly with z. A comparison of the structures with different CS planes revels that the orientation of the CS planes is governed mainly by the stereochemical activity of the lone-electron-pair cations inside the perovskite blocks.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 11
DOI: 10.1021/ic4012845
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“Expanding the Ruddlesden-Popper manganite family : the n=3 La3.2Ba0.8Mn3O10 Member”. Hadermann J, Abakumov AM, Tsirlin AA, Rozova MG, Sarakinou E, Antipov EV, Inorganic chemistry 51, 11487 (2012). http://doi.org/10.1021/ic301332e
Abstract: La3.2Ba0.8Mn3O10, a representative of the rare n = 3 members of the Ruddlesden-Popper manganites A(n+1)Mn(n)O(3n+1), was synthesized in an evacuated sealed silica tube. Its crystal structure was refined from a combination of powder X-ray diffraction (PXD) and precession electron diffraction (PED) data, with the rotations of the MnO6 octahedra described within the symmetry-adapted mode approach (space group Cccm, a = 29.068(1) angstrom, b = 5.5504(5) angstrom, c = 5.5412(5) angstrom; PXD RF = 0.053, RP = 0.026; PED RF = 0.248). The perovskite block in La3.2Ba0.8Mn3O10 features an octahedral tilting distortion with out-of-phase rotations of the Mn06 octahedra according to the (Phi,Phi,0)(Phi,Phi,0) mode, observed for the first time in the n = 3 Ruddlesden-Popper structures. The Mn06 octahedra demonstrate a noticeable deformation with the elongation of two apical Mn-O bonds due to the Jahn-Teller effect in the Mn3+ cations. The relationships between the octahedral tilting distortion, the ionic radii of the cations at the A- and B-positions, and the mismatch between the perovslcite and rock-salt blocks of the Ruddlesden-Popper structure are discussed. At low temperatures, La3.2Ba0.8Mn3O10 reveals a sizable remnant magnetization of about 1.3 mu(B)/Mn at 2K, and shows signatures of spin freezing below 150 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 2
DOI: 10.1021/ic301332e
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“The high-temperature polymorphs of K3AlF6”. King G, Abakumov AM, Woodward PM, Llobet A, Tsirlin AA, Batuk D, Antipov EV, Inorganic chemistry 50, 7792 (2011). http://doi.org/10.1021/ic200956a
Abstract: The crystal structures of the three high-temperature polymorphs of K3AlF6 have been solved from neutron powder diffraction, synchrotron X-ray powder diffraction, and electron diffraction data. The β-phase (stable between 132 and 153 °C) and γ-phase (stable between 153 to 306 °C) can be described as unusually complex superstructures of the double-perovskite structure (K2KAlF6) which result from noncooperative tilting of the AlF6 octahedra. The β-phase is tetragonal, space group I4/m, with lattice parameters of a = 13.3862(5) Å and c = 8.5617(3) Å (at 143 °C) and Z = 10. In this phase, one-fifth of the AlF6 octahedra are rotated about the c-axis by 45° while the other four-fifths remain untilted. The large 45° rotations result in edge sharing between these AlF6 octahedra and the neighboring K-centered polyhedra, resulting in pentagonal bipyramidal coordination for four-fifths of the K+ ions that reside on the B-sites of the perovskite structure. The remaining one-fifth of the K+ ions on the B-sites retain octahedral coordination. The γ-phase is orthorhombic, space group Fddd, with lattice parameters of a = 36.1276(4) Å, b = 17.1133(2) Å, and c = 12.0562(1) Å (at 225 °C) and Z = 48. In the γ-phase, one-sixth of the AlF6 octahedra are randomly rotated about one of two directions by 45° while the other five-sixths remain essentially untilted. These rotations result in two-thirds of the K+ ions on the B-site obtaining 7-fold coordination while the other one-third remain in octahedral coordination. The δ-phase adopts the ideal cubic double-perovskite structure, space group Fmm, with a = 8.5943(1) Å at 400 °C. However, pair distribution function analysis shows that locally the δ-phase is quite different from its long-range average crystal structure. The AlF6 octahedra undergo large-amplitude rotations which are accompanied by off-center displacements of the K+ ions that occupy the 12-coordinate A-sites.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 19
DOI: 10.1021/ic200956a
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“Hole doping and structural transformation in CsTl1-xHgxCl3”. Retuerto M, Yin Z, Emge TJ, Stephens PW, Li MR, Sarkar T, Croft MC, Ignatov A, Yuan Z, Zhang SJ, Jin C, Paria Sena R, Hadermann J, Kotliar G, Greenblatt M;, Inorganic chemistry 54, 1066 (2015). http://doi.org/10.1021/ic502400d
Abstract: CsTlCl3 and CsTlF3 perovskites have been theoretically predicted to be superconductors when properly hole-doped. Both compounds have been previously prepared as pure compounds: CsTlCl3 in a tetragonal (I4/m) and a cubic (Fm3̅m) perovskite polymorph and CsTlF3 as a cubic perovskite (Fm3̅m). In this work, substitution of Tl in CsTlCl3 with Hg is reported, in an attempt to hole-dope the system and induce superconductivity. The whole series CsTl1xHgxCl3 (x = 0.0, 0.1, 0.2, 0.4, 0.6, and 0.8) was prepared. CsTl0.9Hg0.1Cl3 is tetragonal as the more stable phase of CsTlCl3. However, CsTl0.8Hg0.2Cl3 is already cubic with the space group Fm3̅m and with two different positions for Tl+ and Tl3+. For x = 0.4 and 0.5, solid solutions could not be formed. For x ≥ 0.6, the samples are primitive cubic perovskites with one crystallographic position for Tl+, Tl3+, and Hg2+. All of the samples formed are insulating, and there is no signature of superconductivity. X-ray absorption spectroscopy indicates that all of the samples have a mixed-valence state of Tl+ and Tl3+. Raman spectroscopy shows the presence of the active TlClTl stretching mode over the whole series and the intensity of the TlClHg mode increases with increasing Hg content. First-principle calculations confirmed that the phases are insulators in their ground state and that Hg is not a good dopant in the search for superconductivity in this system.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 5
DOI: 10.1021/ic502400d
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“Homologous series of layered perovskites An+1BnO3n-1Cl : crystal and magnetic structure of a new oxychloride Pb4BiFe4O11Cl”. Batuk M, Batuk D, Tsirlin AA, Rozova MG, Antipov EV, Hadermann J, Van Tendeloo G, Inorganic chemistry 52, 2208 (2013). http://doi.org/10.1021/ic302667a
Abstract: The nuclear and magnetic structure of a novel oxychloride Pb4BiFe4O11Cl has been studied over the temperature range 1.5700 K using a combination of transmission electron microscopy and synchrotron and neutron powder diffraction [space group P4/mbm, a = 5.5311(1) Å, c = 19.586(1) Å, T = 300 K]. Pb4BiFe4O11Cl is built of truncated (Pb,Bi)3Fe4O11 quadruple perovskite blocks separated by CsCl-type (Pb,Bi)2Cl slabs. The perovskite blocks consist of two layers of FeO6 octahedra located between two layers of FeO5 tetragonal pyramids. The FeO6 octahedra rotate about the c axis, resulting in a √2ap × √2ap × c superstructure. Below TN = 595(17) K, Pb4BiFe4O11Cl adopts a G-type antiferromagnetic structure with the iron magnetic moments confined to the ab plane. The ordered magnetic moments at 1.5 K are 3.93(3) and 3.62(4) μB on the octahedral and square-pyramidal iron sites, respectively. Pb4BiFe4O11Cl can be considered a member of the perovskite-based An+1BnO3n1Cl homologous series (A = Pb/Bi; B = Fe) with n = 4. The formation of a subsequent member of the series with n = 5 is also demonstrated.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 6
DOI: 10.1021/ic302667a
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“Layered perovskite-like Pb2Fe2O5 structure as a parent matrix for the nucleation and growth of crystallographic shear planes”. Batuk D, Hadermann J, Abakumov A, Vranken T, Hardy A, van Bael M, Van Tendeloo G, Inorganic chemistry 50, 4978 (2011). http://doi.org/10.1021/ic200211x
Abstract: The Pb2Fe2O5 compound with a layered intergrowth structure has been prepared by a solid-state reaction at 700 °C. The incommensurate compound crystallizes in a tetragonal system with a = 3.9037(2) Å, c = 3.9996(4) Å, and q = 0.1186(4)c*, or when treated as a commensurate approximant, a = 3.9047(2) Å, c = 36.000(3) Å, space group I4/mmm. The crystal structure of Pb2Fe2O5 was resolved from transmission electron microscopy data. Atomic coordinates and occupancies of the cation positions were estimated from high-angle annular dark-field scanning transmission electron microscopy data. Direct visualization of the positions of the oxygen atoms was possible using annular bright-field scanning transmission electron microscopy. The structure can be represented as an intergrowth of perovskite blocks and partially disordered blocks with a structure similar to that of the Bi2O2 blocks in Aurivillius-type phases. The A-cation positions at the border of the perovskite block and the cation positions in the Aurivillius-type blocks are jointly occupied by Pb2+ and Fe3+ cations, resulting in a layer sequence along the c axis: PbOFeO2PbOFeO2Pb7/8Fe1/8O1xFe5/8Pb3/8O2Fe5/8Pb3/8. Upon heating, the layered Pb2Fe2O5 structure transforms into an anion-deficient perovskite modulated by periodically spaced crystallographic shear (CS) planes. Considering the layered Pb2Fe2O5 structure as a parent matrix for the nucleation and growth of CS planes allows an explanation of the specific microstructure observed for the CS structures in the PbFeO system.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 16
DOI: 10.1021/ic200211x
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“Magnetic and structural studies of the multifunctional material SrFe0.75Mo0.25O3-\text{\textgreek{d}}”. Retuerto M, Li MR, Go YB, Ignatov A, Croft M, Ramanujachary KV, Hadermann J, Hodges JP, Herber RH, Nowik I, Greenblatt M;, Inorganic chemistry 51, 12273 (2012). http://doi.org/10.1021/ic301550m
Abstract: SrFe0.75Mo0.25O3-delta has been recently discovered as an extremely efficient electrode for intermediate temperature solid oxide fuel cells (IT-SOFCs). We have performed structural and magnetic studies to fully characterize this multifunctional material. We have observed by powder neutron diffraction (PND) and transmission electron microscopy (TEM) that its crystal symmetry is better explained with a tetragonal symmetry (I4/mcm space group) than with the previously reported orthorhombic symmetry (Pnma space group). The temperature dependent magnetic properties indicate an exceptionally high magnetic ordering temperature (T-N similar to 750 K), well above room temperature. The ordered magnetic structure at low temperature was determined by PND to be an antiferromagnetic coupling of the Fe cations. Mossbauer spectroscopy corroborated the PND results. A detailed study, with X-ray absorption spectroscopy (XAS), in agreement with the Mossbauer results, confirmed the formal oxidation states of the cations to be mixed valence Fe3+/4+ and Mo6+.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 12
DOI: 10.1021/ic301550m
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“New class of single-source precursors for the synthesis of main group-transition metal oxides: heterobimetallic Pb-Mn \beta-diketonates”. Zhang H, Yang J-H, Shpanchenko RV, Abakumov AM, Hadermann J, Clérac R, Dikarev EV, Inorganic chemistry 48, 8480 (2009). http://doi.org/10.1021/ic901107s
Abstract: Heterometallic lead−manganese â-diketonates have been isolated in pure form by several synthetic methods that include solid-state and solution techniques. Two compounds with different Pb/Mn ratios, PbMn2(hfac)6 (1) and PbMn(hfac)4 (2) (hfac = hexafluoroacetylacetonate), can be obtained in quantitative yield by using different starting materials. Single crystal X-ray investigation revealed that the solid-state structure of 1 contains trinuclear molecules in which lead metal center is sandwiched between two [Mn(hfac)3] units, while 2 consists of infinite chains of alternating [Pb(hfac)2] and [Mn(hfac)2] fragments. The heterometallic structures are held together by strong Lewis acid−base interactions between metal atoms and diketonate ligands acting in chelating-bridging fashion. Spectroscopic investigation confirmed the retention of heterometallic structures in solutions of non-coordinating solvents as well as upon sublimation-deposition procedure. Thermal decomposition of heterometallic diketonates has been systematically investigated in a wide range of temperatures and annealing times. For the first time, it has been shown that thermal decomposition of heterometallic diketonates results in mixed-metal oxides, while both the structure of precursors and the thermolysis conditions have a significant influence on the nature of the resulting oxides. Five different Pb−Mn oxides have been detected by X-ray powder diffraction when studying the decomposition of 1 and 2 in the temperature range 500−800 °C. The phase that has been previously reported as Pb0.43MnO2.18 was synthesized in the pure form by decomposition of 1, and crystallographically characterized. The orthorhombic unit cell parameters of this oxide, obtained by electron diffraction technique, have been subsequently refined using X-ray powder diffraction data. Besides that, a previously unknown lead−manganese oxide has been obtained at low temperature decomposition and short annealing times. The parameters of its monoclinically distorted unit cell have been determined. The EDX analysis revealed that this compound has a Pb/Mn ratio close to 1:4 and contains no appreciable amount of fluorine.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 28
DOI: 10.1021/ic901107s
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“Polar and magnetic layered A-site and rock salt B-site-ordered NaLnFeWO6 (Ln = La, Nd) perovskites”. Retuerto M, Li MR, Ignatov A, Croft M, Ramanujachary KV, Chi S, Hodges JP, Dachraoui W, Hadermann J, Tran TT, Halasyamani PS, Grams CP, Hemberger J, Greenblatt M;, Inorganic chemistry 52, 12482 (2013). http://doi.org/10.1021/ic401491y
Abstract: We have expanded the double perovskite family of materials with the unusual combination of layered order in the A sublattice and rock salt order over the B sublattice to compounds NaLaFeWO6 and NaNdFeWO6. The materials have been synthesized and studied by powder X-ray diffraction, neutron diffraction, electron diffraction, magnetic measurements, X-ray absorption spectroscopy, dielectric measurements, and second harmonic generation. At room temperature, the crystal structures of both compounds can be defined in the noncentrosymmetric monoclinic P2(1) space group resulting from the combination of ordering both in the A and B sublattices, the distortion of the cell due to tilting of the octahedra, and the displacement of certain cations. The magnetic studies show that both compounds are ordered antiferromagnetically below T-N approximate to 25 K for NaLaFeWO6 and at similar to 21 K for NaNdFeWO6. The magnetic structure of NaNdFeWO6 has been solved with a propagation vector k = (1/2 0 1/2) as an antiferromagnetic arrangement of Fe and Nd moments. Although the samples are potential multiferroics, the dielectric measurements do not show a ferroelectric response.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 17
DOI: 10.1021/ic401491y
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“Slicing the Perovskite structure with crystallographic shear planes : the AnBnO3n-2 homologous series”. Abakumov AM, Hadermann J, Batuk M, d' Hondt H, Tyablikov OA, Rozova MG, Pokholok KV, Filimonov DS, Sheptyakov DV, Tsirlin AA, Niermann D, Hemberger J, Van Tendeloo G, Antipov EV, Inorganic chemistry 49, 9508 (2010). http://doi.org/10.1021/ic101233s
Abstract: A new AnBnO3n−2 homologous series of anion-deficient perovskites has been evidenced by preparation of the members with n = 5 (Pb2.9Ba2.1Fe4TiO13) and n = 6 (Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16) in a single phase form. The crystal structures of these compounds were determined using a combination of transmission electron microscopy and X-ray and neutron powder diffraction (S.G. Ammm, a = 5.74313(7), b = 3.98402(4), c = 26.8378(4) Å, RI = 0.035, RP = 0.042 for Pb2.9Ba2.1Fe4TiO13 and S.G. Imma, a = 5.7199(1), b = 3.97066(7), c = 32.5245(8) Å, RI = 0.032, RP = 0.037 for Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16). The crystal structures of the AnBnO3n−2 homologues are formed by slicing the perovskite structure with (01)p crystallographic shear (CS) planes. The shear planes remove a layer of oxygen atoms and displace the perovskite blocks with respect to each other by the 1/2[110]p vector. The CS planes introduce edge-sharing connections of the transition metal−oxygen polyhedra at the interface between the perovskite blocks. This results in intrinsically frustrated magnetic couplings between the perovskite blocks due to a competition of the exchange interactions between the edge- and the corner-sharing metal−oxygen polyhedra. Despite the magnetic frustration, neutron powder diffraction and Mssbauer spectroscopy reveal that Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 are antiferromagnetically ordered below TN = 407 and 343 K, respectively. The Pb2.9Ba2.1Fe4TiO13 and Pb3.8Bi0.2Ba2Fe4.2Ti1.8O16 compounds are in a paraelectric state in the 5−300 K temperature range.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 23
DOI: 10.1021/ic101233s
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“Sr21Bi8Cu2(CO3)(2)O-41, a Bi5+ Oxycarbonate with an Original 10L Structure”. Malo S, Abakumov AM, Daturi M, Pelloquin D, Van Tendeloo G, Guesdon A, Hervieu M, Inorganic chemistry 53, 10266 (2014). http://doi.org/10.1021/ic501322w
Abstract: The layered structure of Sr21Bi8Cu2(CO3)(2)O-41 (Z = 2) was determined by transmission electron microscopy, infrared spectroscopy, and powder X-ray diffraction refinement in space group P6(3)/mcm (No. 194), with a = 10.0966(3)angstrom and c = 26.3762(5)angstrom. This original 10L-type structure is built from two structural blocks, namely, [Sr15Bi6Cu2(CO3)O-29] and [Sr6Bi2(CO3)O-12]. The Bi5+ cations form [Bi2O10] dimers, whereas the Cu2+ and C atoms occupy infinite tunnels running along (c) over right arrow. The nature of the different blocks and layers is discussed with regard to the existing hexagonal layered compounds. Sr21Bi8Cu2(CO3)(2)O-41 is insulating and paramagnetic.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
DOI: 10.1021/ic501322w
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“Structural and magnetic phase transitions in the AnBnO3n-2 anion-deficient perovskites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16”. Abakumov AM, Batuk M, Tsirlin AA, Tyablikov OA, Sheptyakov DV, Filimonov DS, Pokholok KV, Zhidal VS, Rozova MG, Antipov EV, Hadermann J, Van Tendeloo G;, Inorganic chemistry 52, 7834 (2013). http://doi.org/10.1021/ic3026667
Abstract: Novel anion-deficient perovskite-based ferrites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 were synthesized by solid-state reaction in air. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 belong to the perovskite-based AnBnO3n2 homologous series with n = 5 and 6, respectively, with a unit cell related to the perovskite subcell ap as ap√2 × ap × nap√2. Their structures are derived from the perovskite one by slicing it with 1/2[110]p(1̅01)p crystallographic shear (CS) planes. The CS operation results in (1̅01)p-shaped perovskite blocks with a thickness of (n 2) FeO6 octahedra connected to each other through double chains of edge-sharing FeO5 distorted tetragonal pyramids which can adopt two distinct mirror-related configurations. Ordering of chains with a different configuration provides an extra level of structure complexity. Above T ≈ 750 K for Pb2Ba2BiFe5O13 and T ≈ 400 K for Pb1.5Ba2.5Bi2Fe6O16 the chains have a disordered arrangement. On cooling, a second-order structural phase transition to the ordered state occurs in both compounds. Symmetry changes upon phase transition are analyzed using a combination of superspace crystallography and group theory approach. Correlations between the chain ordering pattern and octahedral tilting in the perovskite blocks are discussed. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 undergo a transition into an antiferromagnetically (AFM) ordered state, which is characterized by a G-type AFM ordering of the Fe magnetic moments within the perovskite blocks. The AFM perovskite blocks are stacked along the CS planes producing alternating FM and AFM-aligned FeFe pairs. In spite of the apparent frustration of the magnetic coupling between the perovskite blocks, all n = 4, 5, 6 AnFenO3n2 (A = Pb, Bi, Ba) feature robust antiferromagnetism with similar Néel temperatures of 623632 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 10
DOI: 10.1021/ic3026667
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“Synthesis, crystal structure, transport, and magnetic properties of novel ternary copper phosphides, A2Cu6P5(A = Sr, Eu) and EuCu4P3”. Charkin DO, Urmanov AV, Kazakov SM, Batuk D, Abakumov AM, Knöner S, Gati E, Wolf B, Lang M, Shevelkov AV, Van Tendeloo G, Antipov EV;, Inorganic chemistry 51, 8948 (2012). http://doi.org/10.1021/ic301033h
Abstract: Three new ternary copper phosphides, Sr2Cu6P5, Eu2Cu6P5, and EuCu4P3, have been synthesized from the elements in evacuated silica capsules. Eu2Cu6P5 and Sr2Cu6P5 adopt the Ca2Cu6P5-type structure, while EuCu4P3 is isostructural to BaMg4Si3 and still remains the only representative of this structure type among the ternary Cu pnictides. All three materials show metallic conductivity in the temperature range 2 K <= T <= 290 K, with no indication for superconductivity. For Eu2Cu6P5 and EuCu4P3, long-range magnetic order was observed, governed by 4f local moments on the Eu atoms with predominant ferromagnetic interactions. While Eu2Cu6P5 shows a single ferromagnetic transition at T-C = 34 K, the magnetic behavior of EuCu4P3 is more complex, giving rise to three consecutive magnetic phase transitions at 70, 43, and 18 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 13
DOI: 10.1021/ic301033h
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“Synthesis, structure, and transport properties of type-I derived clathrate Ge46-xPxSe8-y (x=15.4(1), y=0-2.65) with diverse host-guest bonding”. Kirsanova MA, Mori T, Maruyama S, Matveeva, Batuk D, Abakumov AM, Gerasimenko AV, Olenev AV, Grin Y, Shevelkov AV, Inorganic chemistry 52, 577 (2013). http://doi.org/10.1021/ic3011025
Abstract: A first clathrate compound with selenium guest atoms, [Ge46-xPx]Se8-y square(y) (x = 15.4(1); y = 0-2.65; square denotes a vacancy), was synthesized as a single-phase and structurally characterized. It crystallizes in the space group Fm (3) over bar with the unit cell parameter a varying from 20.310(2) to 20.406(2) angstrom and corresponding to a 2 x 2 x 2 supercell of a usual clathrate-I structure. The superstructure is formed due to the symmetrical arrangement of the three-bonded framework atoms appearing as a result of the framework transformation of the parent clathrate-I structure. Selenium guest atoms occupy two types of polyhedral cages inside the positively charged framework; all selenium atoms in the larger cages form a single covalent bond with the framework atoms, relating the title compounds to a scanty family of semiclathrates. According to the measurements of electrical resistivity and Seebeck coefficient, [Ge46-xPx]Se8-y square(y) is an n-type semiconductor with E-g = 0.41 eV for x = 15.4(1) and y = 0; it demonstrates the maximal thermoelectric power factor of 2.3 x 10(-5) W K-2 m(-1) at 660 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 14
DOI: 10.1021/ic3011025
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“Ternary magnesium rhodium boride Mg2Rh1-xB6+2x with a modified Y2ReB6-type crystal structure”. Alekseeva AM, Abakumov AM, Chizhov PS, Leithe-Jasper A, Schnelle W, Prots Y, Hadermann J, Antipov EV, Grin Y, Inorganic chemistry 46, 7378 (2007). http://doi.org/10.1021/ic7004453
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 12
DOI: 10.1021/ic7004453
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“Cs7Nd11(SeO3)12Cl16 : first noncentrosymmetric structure among alkaline-metal lanthanide selenite halides”. Berdonosov PS, Akselrud L, Prots Y, Abakumov AM, Smet PF, Poelman D, Van Tendeloo G, Dolgikh VA, Inorganic chemistry 52, 3611 (2013). http://doi.org/10.1021/ic301442f
Abstract: Cs7Nd11(SeO3)(12)Cl-16, the complex selenite chloride of cesium and neodymium, was synthesized in the NdOCl-SeO2-CsCl system. The compound has been characterized using single-crystal X-ray diffraction, electron diffraction, transmission electron microscopy, luminescence spectroscopy, and second-harmonic-generation techniques. Cs7Nd11(SeO3)(12)Cl-16 crystallizes in an orthorhombic unit cell with a = 15.911(1) angstrom, b = 15.951(1) angstrom, and c = 25.860(1) angstrom and a noncentrosymmetric space group Pna2(1) (No. 33). The crystal structure of Cs7Nd11(SeO3)(12)Cl-16 can be represented as a stacking of Cs7Nd11(SeO3)(12) lamellas and CsCl-like layers. Because of the layered nature of the Cs7Nd11(SeO3)(12)Cl-16 structure, it features numerous planar defects originating from occasionally missing the CsCl-like layer and violating the perfect stacking of the Cs7Nd11(SeO3)(12)Cl-16 lamellas. Cs7Nd11(SeO3)(12)Cl-16 represents the first example of a noncentrosymmetric structure among alkaline-metal lanthanide selenite halides. Cs7Nd11(SeO3)(12)Cl-16 demonstrates luminescence emission in the near-IR region with reduced efficiency due to a high concentration of Nd3+ ions causing nonradiative cross-relaxation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 10
DOI: 10.1021/ic301442f
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“Na2/7Gd4/7MoO4 : a modulated scheelite-type structure and conductivity properties”. Morozov V, Arakcheeva A, Redkin B, Sinitsyn V, Khasanov S, Kudrenko E, Raskina M, Lebedev O, Van Tendeloo G, Inorganic chemistry 51, 5313 (2012). http://doi.org/10.1021/ic300221m
Abstract: Scheelite-type compounds with the general formula (A1,A2)n[(B1,B2)O4]m (2/3 ≤ n/m ≤ 3/2) are the subject of large interest owing to their stability, relatively simple preparation, and optical properties. The creation of cation vacancies (□) in the scheelite-type framework and the ordering of A cations and vacancies can be a new factor in controlling the scheelite-type structure and properties. For a long time, cation-deficient Nd3+:M2/7Gd4/7□1/7MoO4 (M = Li, Na) compounds were considered as potential lasers with diode pumping. They have a defect scheelite-type 3D structure (space group I41/a) with a random distribution of Li+(Na+), Gd3+, and vacancies in the crystal. A Na2/7Gd4/7MoO4 single crystal with scheelite-type structure has been grown by the Czochralski method. Transmission electron microscopy revealed that Na2/7Gd4/7MoO4 has a (3 + 2)D incommensurately modulated structure. The (3 + 2)D incommensurately modulated scheelite-type cation-deficient structure of Na2/7Gd4/7MoO4 [super space group I4̅ (αβ0,βα0)00] has been solved from single-crystal diffraction data. The solution of the (3 + 2)D incommensurately modulated structure revealed the partially disordered distribution of vacancies and Na and Gd cations. High-temperature conductivity measurements performed along the [100] and [001] orientation of the single crystal revealed that the conductivity of Na2/7Gd4/7MoO4 at T = 973 K equals σ = 1.13 × 105 Ω1 cm1.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 37
DOI: 10.1021/ic300221m
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