TY - CHAP A1 - Schmidt, Peer A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus ED - Ferreira, Sukarno T1 - Advanced Topics on Crystal Growth N2 - Chemical Vapor Transport Reactions–Methods, Materials, Modeling: A variety of processes of crystal growth proceeds via the gas phase. A short comparative overview on gas phase transports is given here. In the main the concept of Chemical Vapor Transport Reactions is presented. KW - crystal growth, inorganic materials Y1 - 2013 UR - http://www.intechopen.com/books/advanced-topics-on-crystal-growth/chemical-vapor-transport-reactions-methods-materials-modeling SN - 978-953-51-1010-1 U6 - https://doi.org/10.5772/55547 SP - 228 EP - 305 PB - Intech Open CY - Rijeka ET - 1. Auflage ER - TY - BOOK A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemical Vapor Transport Reactions N2 - This comprehensive handbook covers the diverse aspects of chemical vapor transport reactions from basic research to important practical applications. The book begins with an overview of models for chemical vapor transport reactions and then proceeds to treat the specific chemical transport reactions for the elements, halides, oxides, sulfides, selenides, tellurides, pnictides, among others. Aspects of transport from intermetallic phases, the stability of gas particles, thermodynamic data, modeling software and laboratory techniques are also covered. Selected experiments using chemical vapor transport reactions round out the work, making this book a useful reference for researchers and instructors in solid state and inorganic chemistry. KW - Chemical Engineering; Solid State Chemistry; Inorganic Synthesis; Crystal Growth Y1 - 2012 UR - http://www.degruyter.com/view/product/129219 SN - 978-3-11-025464-8 PB - De Gruyter CY - Berlin ET - 1. Auflage ER - TY - BOOK A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemische Transportreaktionen N2 - Chemische Transportreaktionen weisen ein gemeinsames Merkmal auf: In Gegenwart eines gasförmigen Reaktionspartners, des Transportmittels, wird eine feste oder flüssige Komponente verflüchtigt. An anderer Stelle scheidet sie sich meist in Form gut ausgebildeter Kristalle wieder ab. So ist der Chemische Transport z. B. für den Festkörperchemiker ein unentbehrliches Verfahren zur Herstellung reiner, gut kristallisierter Feststoffe. Als umfassendes Handbuch behandelt dieses Werk die vielseitigen Aspekte von chemischen Transportreaktionen: Von der Grundlagenforschung bis hin zur praktischen Bedeutung, beispielsweise für die Funktionsweise von Halogenlampen. KW - Festkörperchemie; Transportreaktionen; Synthesemethoden; Chemische Verfahrenstechnik Y1 - 2011 UR - http://www.degruyter.com/view/product/174044 SN - 978-3-11-024897-5 PB - De Gruyter CY - Berlin ET - 1. Auflage ER - TY - GEN A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemical Vapor Transport Reactions – A Historical Review T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - Since their first recognition in mineral forming processes some 150 years ago chemical vapor transport reactions (CVTR) have attracted continuous scientific interest. Due to the pioneering work of Harald Schäfer quantitative understanding and exploitation of transport reactions for crystal growth, synthesis, investigation of high-temperature gas species, and thermodynamic studies have become possible. Renewed interest in CVT is triggered by the demand of material sciences for novel compounds with tailor-made physical properties and by the need for efficient recycling strategies for various metals from industrial waste. KW - Crystal growth;CVT;Thermodynamic modeling;Transport balance;High-temperature reactions Y1 - 2013 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201300048/abstract U6 - https://doi.org/10.1002/zaac.201300048 SN - 1521-3749 VL - Vol. 639 IS - 2 SP - 219 EP - 229 ER - TY - GEN A1 - Schöneich, Michael A1 - Schmidt, Marcus P. A1 - Schmidt, Peer T1 - Chemical Vapour Transport of Bismuth and Antimony Chalcogenides M2Q3 (M = Sb, Bi, Q = Se, Te) T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - Thermodynamic modelling of the ternary systems M/Q/I (M = Sb, Bi, Q = Se, Te) indicated solid-gas equilibria suitable for chemical vapour transport of bismuth and antimony chalcogenides. The predictions of the modelling were confirmed by transport experiments on a transport balance. The optimum transport conditions using iodine as transport agent were determined for all systems to: ϑsource = 500 °C and ϑsink = 450 °C. For ΔT > 50 K the sequential transport of chalcogenide iodides MQI followed by M2Q3 occurs. Thermodynamic standard data of the gas species SbI(g) were concluded from equilibrium calculations: ΔH0f,298(SbI(g)) = 106 ± 3 kJ·mol–1; S0298(SbI(g)) = 255 ± 3 J·mol–1·K–1; Cp(SbI(g)) = 37 ± 1 J·mol–1·K–1 KW - Antimony KW - Bismuth KW - Selenium KW - Tellurium KW - Chemical vapor transport KW - Thermodynamic modelling Y1 - 2010 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201000149/full U6 - https://doi.org/10.1002/zaac.201000149 SN - 1521-3749 VL - 636 IS - 9-10 SP - 1810 EP - 1816 ER - TY - CHAP A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer ED - Dronskowski, Richard ED - Kikkawa, Shinichi ED - Stein, Andreas T1 - Crystal Growth Via the Gas Phase by Chemical Vapor Transport Reactions T2 - Handbook of Solid State Chemistry, Volume 2: Synthesis N2 - The term chemical vapor transport (CVT) summarizes a variety of reactions that show one common feature: a condensed phase, typically a metallic or salt like solid, is volatilized in the presence of a gaseous reactant, the so-called transport agent, and deposits elsewhere, usually in the form of crystals. The deposition will take place if the site of volatilization and the site of crystallization have different temperatures. In many cases, chemical vapor transport is associated with a purification effect. CVT-reactions of elements, oxides, sulfides, selenides, tellurides, phosphates, sulfates, halides, oxide halides, phosphides, arsenides, intermetallics, and so on, are known. KW - Crystal growth KW - Solid state chemistry Y1 - 2017 SN - 978-3-527-32587-0 PB - Wiley-VCH CY - Weinheim ER - TY - BOOK A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemical vapor transport reactions N2 - This comprehensive handbook covers the diverse aspects of chemical vapor transport reactions from basic research to important practical applications. The book begins with an overview of models for chemical vapor transport reactions and then proceeds to treat the specific chemical transport reactions for the elements, halides, oxides, sulfides, selenides, tellurides, pnictides, among others. Aspects of transport from intermetallic phases, the stability of gas particles, thermodynamic data, modeling software and laboratory techniques are also covered. Selected experiments using chemical vapor transport reactions round out the work, making this book a useful reference for researchers and instructors in solid state and inorganic chemistry. KW - Crystal growth Y1 - 2016 SN - 978-3-11-048349-9 PB - De Gruyter CY - Berlin ER - TY - BOOK A1 - Binnewies, Michael A1 - Glaum, Robert A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemische Transportreaktionen N2 - Chemische Transportreaktionen weisen ein gemeinsames Merkmal auf: In Gegenwart eines gasförmigen Reaktionspartners, des Transportmittels, wird eine feste oder flüssige Komponente verflüchtigt. An anderer Stelle scheidet sie sich meist in Form gut ausgebildeter Kristalle wieder ab. So ist der Chemische Transport z. B. für den Festkörperchemiker ein unentbehrliches Verfahren zur Herstellung reiner, gut kristallisierter Feststoffe. Als umfassendes Handbuch behandelt dieses Werk die vielseitigen Aspekte von Chemischen Transportreaktionen: Von der Grundlagenforschung bis hin zur praktischen Bedeutung, beispielsweise für die Funktionsweise von Halogenlampen. KW - Kristallzüchtung Y1 - 2016 SN - 978-3-11-048350-5 PB - De Gruyter CY - Berlin ER - TY - GEN A1 - Binnewies, Michael A1 - Schmidt, Marcus A1 - Schmidt, Peer T1 - Chemical Vapor Transport Reactions – Arguments for Choosing a Suitable Transport Agent T2 - Zeitschrift für Anorganische und Allgemeine Chemie N2 - A variety of processes of crystal growth proceeds via the gas phase. If the initial solid material is volatilized in a heterogeneous reaction under presence of a gaseous reactant, the transport agent, the term Chemical Vapor Transport Reaction (CVT) is applied. Crystallization processes by CVT are known for both elements, intermetallics, binary and complex oxides, halides, chalcogenides, and pnictides. Even if the formation of volatile halides is a common feature of almost all vapor transport reactions, significant differences are there concerning the choice of a suitable transport agent depending on the nature of the initial solid phase. Actually, the appropriateness of transport agents for the respective transport reaction can be described in a thermodynamic way. Besides some basic principles for systematic evaluation more practical recommendations for suitable experimental conditions are given for CVT of different classes of inorganic materials. KW - Crystal growth KW - Chemical vapor transport Y1 - 2017 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201700055/epdf U6 - https://doi.org/10.1002/zaac.201700055 SN - 1521-3749 VL - 643 IS - 21 SP - 1295 EP - 1311 ER - TY - GEN A1 - Eckstein, Nadine A1 - Hohmann, Andrea A1 - Weihrich, Richard A1 - Nilges, Tom A1 - Schmidt, Peer T1 - Synthesis and Phase Relations of Single-Phase Fibrous Phosphorus T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - Fibrous phosphorus is one of the known crystalline allotropes under standard pressure conditions. It has been predicted prior to its successful synthesis and structural characterization. The allotrope consists of parallel, tubular double strands of phosphorus, in contrast to the violet form of Hittorf's phosphorus, where the same strands are arranged in a perpendicular orientation towards each other. This structural similarity results in an almost identical energetic stability leading to a somehow problematic realization of single-phase materials. We herein report on the successful synthesis route to single phase fibrous phosphorus and the in situ characterization of its formation via the gas phase applying CuCl2 as a mineralizer. The sublimation pressure of fibrous phosphorus is slightly lower than the one of the black allotrope. This behavior indicates thermodynamic stability of fibrous phosphorus. KW - Allotropes;Phosphorus;High temperature gas balance Y1 - 2013 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201300327/abstract U6 - https://doi.org/10.1002/zaac.201300327 SN - 1521-3749 VL - Vol. 639 IS - 15 SP - 2741 EP - 2743 ER - TY - GEN A1 - Bawohl, Melanie A1 - Nilges, Tom A1 - Schmidt, Peer T1 - Temperature Initiated P-Polymerization in Solid [Cd3Cu]CuP10 T2 - Inorganic chemistry N2 - [Cd3Cu]CuP10 is the first representative of a class of compounds featuring polyphosphidic adamantine-analogous [P10] units, which tend to be fragmented and polymerized to [P6] rings and tubular [P26] units in the solid state. A new polyphosphide with nominal composition Cd15Cu10P46 results, featuring isolated and polymerized polyanions. Thermoanalytic experiments and phase analytic measurements substantiated the consecutive loss of P4 and Cd of the starting material via different intermediate steps. After P4 loss, the new polyphosphide occurred followed by various binary copper phosphides to the final product Cu3P. KW - Thermal Analysis, Solid State Synthesis, Crystal Structure, Polyphosphide Y1 - 2013 UR - http://pubs.acs.org/doi/abs/10.1021/ic401508n U6 - https://doi.org/10.1021/ic401508n SN - 1520-510X VL - 52 IS - 20 SP - 11895 EP - 11901 ER - TY - GEN A1 - Efimova, Anastasia A1 - Hubrig, Grit A1 - Schmidt, Peer T1 - Thermal stability and crystallization behavior of imidazolium halide ionic liquids T2 - Thermochimica Acta N2 - The 1-butyl-3-methylimidazolium halide ionic liquids are stable up to temperatures of 246(1) °C ([BMIm]Cl), 260(1) °C ([BMIm]Br), and 238(1) °C ([BMIm]I). The thermal decomposition proceeds in thermogravimetric measurements with a total mass loss of 100%. Using evolved gas analysis (EGA) a complete degradation of [BMIm]X ionic liquids under formation of characteristic fragments CH3+, NHn+, C4Hn+, and CH3X+ (X = Cl, Br, I) has been observed. [BMIm]Cl shows enantiotropic polymorphism with a phase transition temperature at 30(1) °C, and melts at 74(1) °C (ΔHfus = 18 ± 0.5 kJ mol−1). Spontaneous e-crystallization and reversible phase transition have been found for cooling of the substance.[BMIm]Br melts at 78(1) °C (ΔHfus = 29 ± 0.5 kJ mol−1). The re-crystallization fails and thus a glassy solid is formed. The glass transition temperature is about −65 °C, the cold crystallization occurs between −30 and −20 °C. The application of both homogeneous and heterogeneous nucleation agents does not interfere the glassy state. [BMIm]I undergo solidification without crystallization. The melting effect for the amorphous substance arise at −70(5) °C with ΔHfus = 0.4 ± 0.2 kJ mol−1. KW - Ionic liquids (ILs); 1-butyl-3-methylimidazolium salts ([BMIm] salts); Thermal decomposition; Glass formation; Nucleation. Y1 - 2013 UR - http://www.sciencedirect.com/science/article/pii/S0040603113004875 U6 - https://doi.org/10.1016/j.tca.2013.09.023 SN - 0040-6031 VL - Vol. 573 SP - 162 EP - 169 ER - TY - GEN A1 - Efimova, Anastasia A1 - Pinnau, Sebastian A1 - Mischke, Matthias A1 - Breitkopf, Cornelia A1 - Ruck, Michael A1 - Schmidt, Peer T1 - Development of salt hydrate eutectics as latent heat storage for air conditioning and cooling T2 - Thermochimica Acta N2 - Sustainable air conditioning systems require heat reservoirs that operate between 4 and 20 ◦C. A systematic search for binary and ternary eutectics of inorganic salts and salt hydrates with melting temperatures in this temperature regime and with high enthalpies of fusion has been performed by means of differential scanning calorimetry (DSC). Promising results were obtained for the pseudo-ternary system Zn(NO3)2·6H2O, Mn(NO3)2·4H2O, and KNO3 with the melting temperature range 18–21 ◦C and the enthalpy of fusion of about 110 kJ kg−1. Suitable nucleating and thickening agents have been found and tested to prevent the mixture from supercooling and phase separation. KW - Phase change material (PCM); Latent heat thermal energy storage (LHTES); Cold storage; Salt hydrate eutectics Y1 - 2014 UR - http://www.sciencedirect.com/science/article/pii/S004060311300573X U6 - https://doi.org/10.1016/j.tca.2013.11.011 SN - 0040-6031 VL - 45 IS - 575 SP - 276 EP - 278 ER - TY - GEN A1 - Pielnhofer, Florian A1 - Schöneich, Michael A1 - Lorenz, Tobias A1 - Yan, Wenjie A1 - Nilges, Tom A1 - Weihrich, Richard A1 - Schmidt, Peer T1 - A rational approach to IrPTe – DFT and CalPhaD studies on phase stability, formation and structure of IrPT e T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - Phase formation, stability, crystal and electronic structures of IrPTe are investigated from experiment and quantum chemical calculations. The phase formation is studied from thermodynamic data and CalPhaD modeling. Applying a high-temperature gas-balance a formation pathway for IrPTe is studied from the elements and the binary parent compounds IrTe2 and IrP2. The obtained paracostibite (CoSbS) type structure contains rarely occurring heteroatomic P-Te dumbbells. The stability of IrPTe and the found structure is studied from DFT calculations with respect to the elements, IrTe2 and IrP2, and possible polymorphs. Probable metastable modifications with XY dumbbells (as known for isoelectronic compounds like CoAsS) are obtained from systematic DFT modelling. Phase transitions are predicted form the equation of states (EOS). According to its electronic band structure IrPTe is predicted as small gap (Eg = 0.5 eV) semiconductor. KW - phase stability KW - DFT KW - gas balance KW - thermodynamic modelling KW - structure prediction Y1 - 2015 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201500149/abstract U6 - https://doi.org/10.1002/zaac.201500149 SN - 1521-3749 VL - 641 IS - 6 SP - 1099 EP - 1105 ER - TY - GEN A1 - Efimova, Anastasia A1 - Pfützner, Linda A1 - Schmidt, Peer T1 - Thermal Stability and Decomposition Mechanism of 1-Ethyl-3-Methylimidazolium Halides T2 - Thermochimica Acta N2 - The thermochemical behavior of 1-ethyl-3-methylimidazolium [EMIm] halides (Cl, Br and I) has been investigated for their crystalline and liquid states in the temperature range from −90 °C to 600 °C using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The temperatures and enthalpies of phase transitions have been determined: Tfus = 86(1) °C, ΔHfus = 14.2(0.7) kJ mol−1 ([EMIm]Cl); Tfus = 67(1) °C, ΔHfus = 19.3(0.7) kJ mol−1 ([EMIm]Br); and Tfus = 74(1) °C, ΔHfus = 16.9(0.6) kJ mol−1 ([EMIm]I). The decomposition temperatures, determined by onset of DTG at 1 K min−1 are 233(5) °C ([EMIm]Cl), 246(5) °C ([EMIm]Br), and 249(5) °C ([EMIm]I). The maximum operation temperature (MOT) has been estimated based on dynamic TGA for an operation time of 24 h: 132 °C ([EMIm]Cl), 149 °C ([EMIm]Br), 139 °C ([EMIm]I) and 8000 h: 76 °C ([EMIm]Cl), 90 °C ([EMIm]Br), 77 °C ([EMIm]I). The decomposition products of the investigated ionic liquids (ILs) after heating experiments were identified by means of TGA complemented with mass spectrometry (MS), for establishment of the mechanism of thermal decomposition of the ILs. Complete degradation of [EMIm]X ionic liquids occurs under formation of characteristic molecule fragments CH3+, NH+, and X+, CH3X+, C2H5X+ (X = Cl, Br, I). KW - Ionic liquids (ILs) KW - 1-Ethyl-3-methylimidazolium halides ([EMIm] halides) KW - Thermal decomposition mechanism KW - Differential scanning calorimetry (DSC) KW - Thermogravimetric analysis (TGA) KW - Mass spectrometry (MS) KW - Integral isoconversional method KW - Maximum operation temperature (MOT) Y1 - 2015 UR - http://www.sciencedirect.com/science/article/pii/S0040603115000350 U6 - https://doi.org/10.1016/j.tca.2015.02.001 VL - 604 SP - 129 EP - 136 ER - TY - GEN A1 - Groh, Matthias F. A1 - Breternitz, Joachim A1 - Ahmed, Ejaz A1 - Isaeva, Anna A1 - Efimova, Anastasia A1 - Schmidt, Peer A1 - Ruck, Michael T1 - Ionothermal Synthesis, Structure, and Bonding of the Catena-Heteropolycation 1∞[Sb2Se2]+ T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - The reaction of antimony and selenium in the Lewis-acidic ionic liquid 1-butyl-3-methyl-imidazolium tetrachloridoaluminate, [BMIm]Cl·4.7AlCl3, yielded dark-red crystals of [Sb2Se2]AlCl4. The formation starts above 160 °C; at about 190 °C, irreversible decomposition takes place. The compound crystallizes in the triclinic space group Pequation image with a = 919.39(2) pm, b = 1137.92(3) pm, c = 1152.30(3) pm, α = 68.047(1)°, β = 78.115(1)°, γ = 72.530(1)°, and Z = 4. The structure is similar to that of [Sb2Te2]AlCl4 but has only half the number of crystallographically independent atoms. Polycationic chains 1∞[Sb2Se2]+ form a pseudo-hexagonal arrangement along [01-1], which is interlaced by tetrahedral AlCl4– groups. The catena-heteropolycation 1∞[Sb2Se2]+ is a sequence of three different four-membered [Sb2Se2] rings. The chemical bonding scheme, established from the topological analysis of the real-space bonding indicator ELI-D, includes significantly polar covalent bonding in four-member rings within the polycation. The rings are connected into an infinite chain by homonuclear non-polar Sb–Sb bonds and highly polar Sb–Se bonds. Half of the selenium atoms are three-bonded. KW - Chain structures KW - Antimony KW - Heteropolycations KW - Main-group elements KW - Selenium Y1 - 2015 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201400543/abstract U6 - https://doi.org/10.1002/zaac.201400543 SN - 1521-3749 VL - 641 IS - 2 SP - 388 EP - 393 ER - TY - GEN A1 - Scholz, Tanja A1 - Schmidt, Peer T1 - Homogeneity Range of the Zirconium Phosphide Telluride Zr2+xPTe2 and the High Temperature Phase Transformation to Zr2PTe T2 - European Journal of Inorganic Chemistry N2 - The synthesis of the phosphide telluride Zr2+xPTe2 was accomplished by a solid-state reaction from the elements. Le Bail refinements of the as synthesized crystalline powders as well as the thermal decomposition of Zr2PTe2 along the homogeneity range Zr2+xPTe2 under the release of P4(g) and Te2(g) evidences a maximum zirconium content according to the composition Zr2.5PTe2. The thermal decomposition product of Zr2.5PTe2 undergoes a phase transformation to “Zr2PTe” adopting the structure motive of the binary phases ZrTe and ZrTe2. The new phase “Zr2PTe” has a wide homogeneity range Zr2–xP1–yTe1+y tolerating a deficit in the cation position and a mixed occupation of the anions. The composition of the crystalline decomposition product was determined to Zr1.95P0.84Te1.16 by Rietveld refinement and by analysing the elemental composition with ICP-OES. Zr1.95P0.84Te1.16 crystallizes in hexagonal space group P63/mmc (no. 194) with lattice constants: a = 3.8726(1) Å and c = 13.008(1) Å. KW - Phase transitions KW - Phase diagrams KW - Thermal decomposition KW - Structure elucidation KW - Tellurium KW - Phosphide telluride Y1 - 2015 UR - http://onlinelibrary.wiley.com/doi/10.1002/ejic.201403043/abstract U6 - https://doi.org/10.1002/ejic.201403043 SN - 1099-0682 IS - 8 SP - 1457 EP - 1462 ER - TY - GEN A1 - Bachhuber, Frederik A1 - Appen, Jörg von A1 - Dronskowski, Richard A1 - Schmidt, Peer A1 - Nilges, Tom A1 - Pfitzner, Arno A1 - Weihrich, Richard T1 - Van der Waals interactions in selected allotropes of phosphorus T2 - Zeitschrift für Kristallografie N2 - Selected allotropes of phosphorus are investigated by different levels of density functional theory (DFT) calculations to evaluate the relative stability orders with a special focus on the role of van der Waals interactions.Phosphorus is an excellent reference system with a large number of allotropes. Starting from low-dimensional molecular (0D, white P) and polymer structures (1D, P nanorods) to layered (2D, black P) and tubular structures (2D and 3D, crystalline forms of red P), covalent structure motifs are interconnected by van der Waals interactions. They are a key factor for the correct energetic description of all P allotropes. A comparative study is carried out within the local density approximation (LDA) and the generalized gradient approximation (GGA), with and without implementation of a dispersion correction by Grimme (GGA-D2). Our intention is to achieve a reasonable agreement of our calculations with experimental data, the plausibility of energy values, and the treatment of long-range interactions. The effect of van der Waals interactions is exemplified for the interlayer distances of black phosphorous and its electronic structure. KW - allotropes KW - band structure KW - DFT KW - phosphorous KW - stability KW - van der Waals Y1 - 2015 U6 - https://doi.org/10.1515/zkri-2014-1800 SN - 2196-7105 VL - 230 IS - 2 SP - 107 EP - 115 ER - TY - GEN A1 - Bachhuber, Frederik A1 - Appen, Jörg von A1 - Dronskowski, Richard A1 - Schmidt, Peer A1 - Nilges, Tom A1 - Pfitzner, Arno A1 - Weihrich, Richard T1 - The Extended Stability Range of Phosphorus Allotropes T2 - Angewandte Chemie / International edition N2 - Phosphorus displays fascinating structural diversity and the discovery of new modifications continues to attract attention. In this work, a complete stability range of known and novel crystalline allotropes of phosphorus is described for the first time. This includes recently discovered tubular modifications and the prediction of not-yet-known crystal structures of [P12] nanorods and not-yet-isolated [P14] nanorods. Despite significant structural differences, all P allotropes consist of covalent substructures, which are held together by van der Waals interactions. Their correct reproduction by ab initio calculations is a core issue of current research. While some predictions with the established DFT functionals GGA and LDA differ significantly from experimental data in the description of the P allotropes, consistently excellent agreement with the GGA-D2 approach is used to predict the solid structures of the P nanorods. KW - density functional calculations KW - phosphorus KW - structure elucidation KW - van der Waals interactions Y1 - 2014 UR - http://onlinelibrary.wiley.com/doi/10.1002/anie.201404147/full U6 - https://doi.org/10.1002/anie.201404147 SN - 1521-3773 VL - 53 IS - 43 SP - 11629 EP - 11633 ER - TY - GEN A1 - Osters, Oliver A1 - Nilges, Tom A1 - Schöneich, Michael A1 - Schmidt, Peer A1 - Rothballer, Jan A1 - Pielnhofer, Florian A1 - Weihrich, Richard T1 - Cd4Cu7As, the first representative of a fully ordered, orthorhombically distorted MgCu2 Laves phase T2 - Inorganic Chemistry N2 - The ternary Laves phase Cd4Cu7As is the first intermetallic compound in the system Cu–Cd–As and a representative of a new substitution variant for Laves phases. It crystallizes orthorhombically in the space group Pnnm (No. 58) with lattice parameters a = 9.8833(7) Å; b = 7.1251(3) Å; c = 5.0895(4) Å. All sites are fully occupied within the standard deviations. The structure can be described as typical Laves phase, where Cu and As are forming vertex-linked tetrahedra and Cd adopts the structure motive of a distorted diamond network. Cd4Cu7As was prepared from stoichiometric mixtures of the elements in a solid state reaction at 1000 °C. Magnetic measurements are showing a Pauli paramagnetic behavior. During our systematical investigations within the ternary phase triangle Cd–Cu–As the cubic C15-type Laves phase Cd4Cu6.9(1)As1.1(1) was structurally characterized. It crystallizes cubic in the space group Fd3m̅ with lattice parameter a = 7.0779(8) Å. Typically for quasi-binary Laves phases Cu and As are both occupying the 16c site. Chemical bonding, charge transfer and atomic properties of Cd4Cu7As were analyzed by band structure, ELF, and AIM calculations. On the basis of the general formula for Laves phases AB2, Cd is slightly positively charged forming the A substructure, whereas Cu and As represent the negatively charged B substructure in both cases. The crystal structure distortion is thus related to local effects caused by Arsenic that exhibits a larger atomic volume (18 Å3 compared to 13 Å3 for Cu) and higher ionicity in bonding. Y1 - 2012 UR - http://pubs.acs.org/doi/abs/10.1021/ic3005213 U6 - https://doi.org/10.1021/ic3005213 SN - 1520-510X VL - 51 SP - 8119 EP - 8127 ER - TY - GEN A1 - Scholz, Tanja A1 - Dao Quoc, Huong A1 - Schmidt, Peer T1 - Phase barograms – phased diagrams of vapour pressure: Eutectoid Phase Formation in Binary Systems T2 - Thermochimica Acta N2 - Phase barograms are specific representations of conventional (x, T) phase diagrams considering the vapor pressure as additional thermodynamic parameter. Thus, the determination of the vapor pressure is complementary to conventional DTA or DSC measurements. A stringent relationship between the phase diagram and the corresponding phase barogram is derived by thermodynamic considerations of phase relations for complex heterogeneous equilibria. For that purpose, a derivative of the three-dimensional Clausius–Clapeyron equation is utilized. As a result, a validation of DTA/DSC measurements becomes feasible by the transformation of characteristic effects of vapor pressure measurements into thermal effects in conventional phase diagrams. The system CsBr/SeO2 is presented as a case study of systems with a eutectoid phase formation. CsSeO2Br is formed from the binaries at ϑf = 180(5) °C; the compound decomposes peritectically at ϑp = 470(10) °C. KW - Phase barogram KW - Phase diagram KW - Vapor pressure KW - CsBr KW - SeO2 Y1 - 2012 UR - http://www.sciencedirect.com/science/article/pii/S0040603112001979 U6 - https://doi.org/10.1016/j.tca.2012.04.022 VL - 541 SP - 1 EP - 7 ER -