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 - 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 - Günther, David A1 - Beckmann, Jens A1 - Schöneich, Michael A1 - Schmidt, Peer A1 - Klepel, Olaf T1 - Porous concrete as a template for the synthesis of porous carbon materials T2 - Carbon N2 - The potential of industrial porous concrete for using as a template for the synthesis of porous carbon materials has been investigated. Carbon replicas of porous concrete have been prepared by carbonization of sucrose. The pores of the resulting carbon materials range from the macropore to the micropore region, pointing to a hierarchy. Y1 - 2012 UR - http://www.sciencedirect.com/science/article/pii/S000862231200173X?np=y U6 - https://doi.org/10.1016/j.carbon.2012.02.039 SN - 0008-6223 VL - 50 IS - 8 SP - 3092 EP - 3116 ER - TY - GEN A1 - Schmidt, Peer A1 - Schöneich, Michael A1 - Bawohl, Melanie A1 - Nilges, Tom A1 - Weihrich, Richard T1 - Thermal analysis detecting equilibrium conditions: The use of the high temperature gas balance for thermogravimetric measurements T2 - Journal of Thermal Analysis and Calorimetry N2 - Several methods are established in thermal analysis to investigate phase formation, phase transition, and decomposition reactions. The analysis of phase equilibria with volatile components is particularly feasible by using standard method of thermogravimetry. Hardly any investigations of phase formation reactions are possible to realize if one of the components is lost by vaporization. By using the “High-Temperature Gas-Balance” (HTGB), the vapor phase is enclosed in a silica ampoule and thus forms an equilibrium gas phase in permanent contact with the solid phase. The measurement signal Δmmeas is caused by change of the leverage of the horizontal balance support during evaporation and condensation. The application of the HTGB allows the analysis of solid–gas equilibria in the working range from 0.01 till 15 bar at temperatures up to 1,100 °C. The first comparison of evaporation reactions determined by standard thermogravimetric analyses and by measurements using the HTGB is given for the inorganic systems: P, As, SeO2, PtI2, and Hg/I. KW - High-Temperature Gas-Balance KW - Thermogravimetry KW - Vapor pressure KW - Equilibrium measurements Y1 - 2012 UR - http://www.akademiai.com/doi/pdf/10.1007/s10973-011-2107-3 U6 - https://doi.org/10.1007/s10973-011-2107-3 SN - 1572-8943 VL - 110 IS - 3 SP - 1511 EP - 1521 ER - TY - GEN A1 - Osters, Oliver A1 - Nilges, Tom A1 - Bachhuber, Frederik A1 - Pielnhofer, Florian A1 - Weihrich, Richard A1 - Schöneich, Michael A1 - Schmidt, Peer T1 - Synthesis and Identification of Metastable Compounds: Black Arsenic—Science or Fiction? T2 - Angewandte Chemie / International edition N2 - Back in black: All metastable and stable phases can be identified for the solid solution arsenic/phosphorus by a combination of quantum-chemical calculations and investigations of the phase formation. Reaction paths for phase formations and transitions in situ were also evaluated. The results show that orthorhombic black arsenic (o-As) is metastable in pure form and has only been previously obtained by stabilizing impurities. KW - arsenic KW - metastable phases KW - phase formation KW - phosphorus KW - solid-state structures Y1 - 2012 UR - http://onlinelibrary.wiley.com/doi/10.1002/anie.201106479/abstract U6 - https://doi.org/10.1002/anie.201106479 SN - 1521-3773 VL - 51 IS - 12 SP - 2994 EP - 2997 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 - GEN A1 - Schöneich, Michael A1 - Hohmann, Andrea A1 - Schmidt, Peer A1 - Pielnhofer, Florian A1 - Bachhuber, Frederik A1 - Weihrich, Richard A1 - Osters, Oliver A1 - Köpf, Marianne A1 - Nilges, Tom T1 - Element allotropes and polyanion compounds of pnicogenes and chalcogenes: stability, mechanisms of formation, controlled synthesis and characterization T2 - Zeitschrift für Kristallographie - Crystalline Materials N2 - The application of the EnPhaSyn (theoretical Energy diagrams, experimental Phase formation, Synthesis and characterisation) concept is reviewed with respect to prediction of structures and stability of element allotropes and compound polymorphs, their phase formation and transition processes, and their directed synthesis, respectively. Therein, the relative energetical stability (En) of target compounds and possible decomposition are determined from quantum chemical DFT calculations. Phase formation and transition (Pha) is probed by a gas balance method, developed as high temperature gas balance concept. It helped to study the synthesis and stability range of several compounds experimentally. Applications of the concept and synthesis principles (Syn) of non-equilibrium phases are presented for allotropes of P, As, P1-xAsx, as well as binary and ternary compounds including the Zintl and Laves like phases IrPTe, NiP2, CoSbS, NiBiSe, Li0.2CdP2, Cu3CdCuP10, and Cd4Cu7As. KW - Arsenic KW - Phosporus KW - DFT KW - energy diagram KW - polymorph structure Y1 - 2017 UR - https://www.degruyter.com/view/j/zkri.ahead-of-print/zkri-2016-1966/zkri-2016-1966.xml U6 - https://doi.org/10.1515/zkri-2016-1966 SN - 2194-4946 VL - 232 IS - 1-3 SP - 91 EP - 105 ER - TY - GEN A1 - Schöneich, Michael A1 - Lorenz, Tobias A1 - Bawohl, Melanie A1 - Nilges, Tom A1 - Schmidt, Peer T1 - Phase Formation in the System Hg/P/I Induced by Evaporation Pressure T2 - Zeitschrift für Anorganische und Allgemeine Chemie KW - High-temperature Gas-balance Y1 - 2010 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201009042/full U6 - https://doi.org/10.1002/zaac.201009042 N1 - Poster VL - 636 IS - 11 SP - S. 2070 ER - TY - GEN A1 - Schöneich, Michael A1 - Schmidt, Peer T1 - Kinetics of phase formation in solid - gas reactions: Iron and Arsenic T2 - Zeitschrift für Anorganische und Allgemeine Chemie N2 - Based on the experience of thermo-chemical studies on a High-Temperature Gas-Balance a time dependent analysis has been developed for the investigations of the kinetics of solid-gas reactions. The course of solid-gas reactions can be examined unambiguously by separation of the initial solids. By this setup the visualization of different stages of solid-gas reaction (vaporization, phase formation) becomes feasible. Time dependent analysis of the formation of FeAs results in an assignment of the underlying principles of kinetics derived from the conversion factor α. KW - Arsenic KW - High-temperature Gas-balance KW - Thermal analysis Y1 - 2012 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201204026/full U6 - https://doi.org/10.1002/zaac.201204026 VL - 638 IS - 10 SP - S. 1579 ER - TY - GEN A1 - Schmidt, Peer A1 - Schöneich, Michael A1 - Nilges, Tom A1 - Weihrich, Richard T1 - Identification of Metastable States in Heterogeneous Phase Formation T2 - Zeitschrift für Anorganische und Allgemeine Chemie KW - Phosphorus KW - High-temperature Gas-balance Y1 - 2012 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201204134/full U6 - https://doi.org/10.1002/zaac.201204134 N1 - Poster VL - 638 IS - 10 SP - S. 1633 ER -