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 - 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 - 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 - Nilges, Tom A1 - Osters, Oliver A1 - Schmidt, Peer A1 - Schöneich, Michael A1 - Weihrich, Richard A1 - Bachhuber, Frederik T1 - Untersuchungen zur Bildung von schwarzem Arsen T2 - Zeitschrift für Anorganische und Allgemeine Chemie N2 - Das Mineralisatorkonzept für Polypniktide, basierend auf PbI2 als Mineralisator, wurde erfolgreich zur Synthese der festen Lösung von ortho-rhombischem, schwarzen As1–xPx eingesetzt (x = 0.17-1). Die Zellparameter von As0.83P0.17 sind identisch mit den Literaturwerten des As(schwarz). Aus Pulver- und Einkristalldaten bei variabler Zusammensetzung ist es möglich, das Zellvolumen und die Gitterparameter von reinem, schwarzen Arsen abzuleiten. Die Analyse der Phasenbildung basiert auf der Bestimmung der Gleichgewichtsdrücke der Intermediate Au2P3 und Asgrau sowie von PbI2 im Vergleich zu As1–xPx(schwarz): Die Kondensation erfolgt unterhalb 600 °C aus einer komplexen Gasphase (u.a. AsnP4–n). KW - Phosphorus KW - Arsenic KW - Crystal structure Y1 - 2010 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201008019/full U6 - https://doi.org/10.1002/zaac.201008019 VL - 636 IS - 11 SP - S. 46 ER -