@misc{PielnhoferSchoeneichLorenzetal., author = {Pielnhofer, Florian and Sch{\"o}neich, Michael and Lorenz, Tobias and Yan, Wenjie and Nilges, Tom and Weihrich, Richard and Schmidt, Peer}, title = {A rational approach to IrPTe - DFT and CalPhaD studies on phase stability, formation and structure of IrPT e}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {641}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {6}, issn = {1521-3749}, doi = {10.1002/zaac.201500149}, pages = {1099 -- 1105}, abstract = {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.}, language = {en} } @misc{OstersNilgesSchoeneichetal., author = {Osters, Oliver and Nilges, Tom and Sch{\"o}neich, Michael and Schmidt, Peer and Rothballer, Jan and Pielnhofer, Florian and Weihrich, Richard}, title = {Cd4Cu7As, the first representative of a fully ordered, orthorhombically distorted MgCu2 Laves phase}, series = {Inorganic Chemistry}, volume = {51}, journal = {Inorganic Chemistry}, issn = {1520-510X}, doi = {10.1021/ic3005213}, pages = {8119 -- 8127}, abstract = {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) {\AA}; b = 7.1251(3) {\AA}; c = 5.0895(4) {\AA}. 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) {\AA}. 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 {\AA}3 compared to 13 {\AA}3 for Cu) and higher ionicity in bonding.}, language = {en} } @misc{GuentherBeckmannSchoeneichetal., author = {G{\"u}nther, David and Beckmann, Jens and Sch{\"o}neich, Michael and Schmidt, Peer and Klepel, Olaf}, title = {Porous concrete as a template for the synthesis of porous carbon materials}, series = {Carbon}, volume = {50}, journal = {Carbon}, number = {8}, issn = {0008-6223}, doi = {10.1016/j.carbon.2012.02.039}, pages = {3092 -- 3116}, abstract = {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.}, language = {en} } @misc{SchmidtSchoeneichBawohletal., author = {Schmidt, Peer and Sch{\"o}neich, Michael and Bawohl, Melanie and Nilges, Tom and Weihrich, Richard}, title = {Thermal analysis detecting equilibrium conditions: The use of the high temperature gas balance for thermogravimetric measurements}, series = {Journal of Thermal Analysis and Calorimetry}, volume = {110}, journal = {Journal of Thermal Analysis and Calorimetry}, number = {3}, issn = {1572-8943}, doi = {10.1007/s10973-011-2107-3}, pages = {1511 -- 1521}, abstract = {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.}, language = {en} } @misc{OstersNilgesBachhuberetal., author = {Osters, Oliver and Nilges, Tom and Bachhuber, Frederik and Pielnhofer, Florian and Weihrich, Richard and Sch{\"o}neich, Michael and Schmidt, Peer}, title = {Synthesis and Identification of Metastable Compounds: Black Arsenic—Science or Fiction?}, series = {Angewandte Chemie / International edition}, volume = {51}, journal = {Angewandte Chemie / International edition}, number = {12}, issn = {1521-3773}, doi = {10.1002/anie.201106479}, pages = {2994 -- 2997}, abstract = {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.}, language = {en} } @misc{SchoeneichSchmidtSchmidt, author = {Sch{\"o}neich, Michael and Schmidt, Marcus P. and Schmidt, Peer}, title = {Chemical Vapour Transport of Bismuth and Antimony Chalcogenides M2Q3 (M = Sb, Bi, Q = Se, Te)}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {636}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {9-10}, issn = {1521-3749}, doi = {10.1002/zaac.201000149}, pages = {1810 -- 1816}, abstract = {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}, language = {en} } @misc{SchoeneichHohmannSchmidtetal., author = {Sch{\"o}neich, Michael and Hohmann, Andrea and Schmidt, Peer and Pielnhofer, Florian and Bachhuber, Frederik and Weihrich, Richard and Osters, Oliver and K{\"o}pf, Marianne and Nilges, Tom}, title = {Element allotropes and polyanion compounds of pnicogenes and chalcogenes: stability, mechanisms of formation, controlled synthesis and characterization}, series = {Zeitschrift f{\"u}r Kristallographie - Crystalline Materials}, volume = {232}, journal = {Zeitschrift f{\"u}r Kristallographie - Crystalline Materials}, number = {1-3}, issn = {2194-4946}, doi = {10.1515/zkri-2016-1966}, pages = {91 -- 105}, abstract = {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.}, language = {en} } @misc{SchoeneichLorenzBawohletal., author = {Sch{\"o}neich, Michael and Lorenz, Tobias and Bawohl, Melanie and Nilges, Tom and Schmidt, Peer}, title = {Phase Formation in the System Hg/P/I Induced by Evaporation Pressure}, series = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, volume = {636}, journal = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, number = {11}, doi = {10.1002/zaac.201009042}, pages = {S. 2070}, language = {en} } @misc{SchoeneichSchmidt, author = {Sch{\"o}neich, Michael and Schmidt, Peer}, title = {Kinetics of phase formation in solid - gas reactions: Iron and Arsenic}, series = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, volume = {638}, journal = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, number = {10}, doi = {10.1002/zaac.201204026}, pages = {S. 1579}, abstract = {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.}, language = {en} } @misc{SchmidtSchoeneichNilgesetal., author = {Schmidt, Peer and Sch{\"o}neich, Michael and Nilges, Tom and Weihrich, Richard}, title = {Identification of Metastable States in Heterogeneous Phase Formation}, series = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, volume = {638}, journal = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, number = {10}, doi = {10.1002/zaac.201204134}, pages = {S. 1633}, language = {en} }