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 - 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 - Rudorf, Wolfram W. A1 - Schmidt, Peer T1 - Studies on synthetic galloalunites AGa3(SO4)2(OH)6: Synthesis, Thermal analysis, and X-ray characterization T2 - Thermochimica Acta N2 - Stoichiometric end member galloalunites of the general formula AGa3(SO4)2(OH)6, with A = Na+, K+, Rb+, H3O+, and NH4+ have been synthesized under hydrothermal conditions. These galloalunites were characterized by chemical methods, thermal analysis (DSC, TG coupled with mass spectroscopy), and powder X-ray diffraction (XRD). The stages of thermal decomposition of sodium, potassium and rubidium galloalunite show a common decomposition mechanism forming β-Ga2O3 and A2SO4 (A = Na+, K+, and Rb+) while ammonium and oxonium galloalunite decompose under formation of pure β-Ga2O3. The thermogravimetric results confirmed the analytical results on the galloalunites and thereby verified the stoichiometry of these synthetic products. Galloalunites with different monovalent cations in A site (i.e. Na+, K+, Rb+, H3O+ and NH4+) crystallize in the rhombohedral space group R-3m (#166). The effects of substitution on the unit cell parameters are rationalized in terms of the structural arrangements in galloalunites. The unit cell parameter c increases with increasing effective ionic radii of the cation in the A site, whereas the parameter a changes to a much lesser degree. KW - Synthesis KW - Galloalunites KW - X-ray diffraction KW - Unit cell parameters KW - Thermal analysis Y1 - 2011 UR - http://www.sciencedirect.com/science/article/pii/S0040603111002310 U6 - https://doi.org/10.1016/j.tca.2011.04.013 VL - 521 IS - 1-2 SP - 112 EP - 120 ER - TY - GEN A1 - Zhang, Xi A1 - Herklotz, Frank A1 - Hieckmann, Ellen A1 - Weber, Jörg A1 - Schmidt, Peer T1 - Vapor phase growth of ZnO single crystals T2 - Journal of Vacuum Science and Technology : A N2 - Zinc oxide is a promising wide band gap semiconductor for future optoelectronic devices. Today ZnO bulk single crystals are grown by three different techniques: hydrothermally, from the melt, and by chemical vapor transport. For our studies, the authors employed in addition a simple and low cost vapor phase method which gives us good quality crystals and flexibility in crystal doping. The as-grown needle-shaped single crystals were characterized by resistivity measurements, scanning electron microscopy, electron backscatter diffraction, and low temperature photoluminescence spectroscopy. Y1 - 2011 UR - http://scitation.aip.org/content/avs/journal/jvsta/29/3/10.1116/1.3553461 U6 - https://doi.org/10.1116/1.3553461 VL - 29 SP - 03A107 ER - TY - GEN A1 - Tschulik, Kristina A1 - Hoffmann, Stefan A1 - Fokwa, Boniface P. T. A1 - Gilleßen, Michael A1 - Schmidt, Peer T1 - Studies regarding the homogeneity range of the zirconium phosphide telluride Zr2+xPTe2 T2 - Solid State Sciences N2 - The phosphide tellurides Zr2+δPTe2 (0 ≤ δ ≤ 1) can be synthesized from the elements in a solid state reaction or by thermal decomposition of Z. Zr2PTe2 decomposes under release of Te2(g) + P4(g) forming the homogeneity range Zr2+δPTe2. The growth of single crystals of Zr2+δPTe2 succeeded by chemical vapour transport using iodine as transport agent from 830 °C in direction of higher temperatures up to 900 °C. Zr2+δPTe2 crystallizes in the rhombohedral space group R-3m (no. 166) with lattice parameters a = 383(1)…386(1) pm and c = 2935(4)…2970(4) pm for δ = 0…1, respectively. Single crystal data have been determined for Zr2.40(2)PTe2 with lattice parameters a = 385.24(4) pm and c = 2967.8(4) pm. The electronic structure and chemical bonding in Zr2+δPTe2 was investigated by the linear muffin–tin orbital (LMTO) method. Both Zr2PTe2 and Zr3PTe2 show non-vanishing DOS values at the Fermi level (EF) indicating metallic character. According to COHP bonding analyses, mainly the heteroatomic Zr–P and Zr–Te bonds are responsible for the structural stability of Zr3PTe2. The new Zr2–Te bond, which is not present in Zr2PTe2, is stronger than Zr1–Te and is thought to be responsible for the stability of phases having Zr in excess. KW - Zirconium phosphide telluride KW - Homogeneity range KW - Thermal decomposition KW - Crystal structure KW - Chemical bonding Y1 - 2010 UR - http://www.sciencedirect.com/science/article/pii/S1293255810003614 U6 - https://doi.org/10.1016/j.solidstatesciences.2010.08.022 SN - 1293-2558 VL - 12 IS - 12 SP - 2030 EP - 2035 ER - TY - GEN A1 - Jahn, Stephan F. A1 - Blaudeck, Thomas A1 - Baumann, Reinhard R. A1 - Jakob, Alexander A1 - Ecorchard, Petra A1 - Rüffer, Tobias A1 - Lang, Heinrich A1 - Schmidt, Peer T1 - Inkjet Printing of Conductive Silver Patterns by Using the First Aqueous Particle-Free MOD Ink without Additional Stabilizing Ligands T2 - Chemistry of Materials N2 - The chemical and physical properties of [AgO2C(CH2OCH2)3H] (3) and its use as an aqueous, ligand-free MOD ink (MOD = metal−organic decomposition) for piezo inkjet printing is discussed. The printed, thermal, or photochemical sintered silver features are electrically conductive on glass (2.7 × 107 S m−1) and PET (PET = polyethylene terephthalate) substrates (1.1 × 107 S m−1) corresponding to 43% and 18% of the bulk silver conductivity. Conducted tape tests show the suitability of the ink for particularly polymer substrates. TG-MS studies demonstrate a two-step decomposition for the conversion of 3 to elemental silver. The structure of 3 in the solid state was determined by single X-ray structure determination. Y1 - 2010 UR - http://pubs.acs.org/doi/abs/10.1021/cm9036428 U6 - https://doi.org/10.1021/cm9036428 SN - 1520-5002 VL - 22 IS - 10 SP - 3067 EP - 3071 ER - TY - GEN A1 - Müller, Carola J. A1 - Schwarz, Ulrich A1 - Schmidt, Peer A1 - Schnelle, Walter A1 - Doert, Thomas T1 - High-Pressure Synthesis, Crystal Structure, and Properties of GdS2 with Thermodynamic Investigations in the Phase Diagram Gd-S, T2 - Zeitschrift für anorganische und allgemeine Chemie N2 - Gadolinium disulfide was prepared by high-pressure synthesis at 8 GPa and 1173 K. It crystallizes in the monoclinic space group P121/a1 (No. 14) with lattice parameters a = 7.879(1) Å; b = 3.936(1) Å, c = 7.926(1) Å and β = 90.08(1)°. The crystal structure is a twofold superstructure of the aristotype ZrSSi and consists of puckered cationic [GdS]+ double slabs that are sandwiched by planar sulfur sheets containing S22– dumbbells. The thermal decomposition of GdS2 proceeds via the sulfur-deficient polysulfides GdS1.9, GdS1.85 and GdS1.77 and eventually results in the sesquisulfide Gd2S3. GdS2 is a paramagnetic semiconductor which orders antiferromagnetically at TN = 7.7(1) K. A metamagnetic transition is observed in the magnetically ordered state. KW - Polysulfides KW - Gadolinium KW - High-pressure synthesis KW - X-ray diffraction KW - Phase diagrams Y1 - 2010 UR - http://onlinelibrary.wiley.com/doi/10.1002/zaac.201000015/full U6 - https://doi.org/10.1002/zaac.201000015 SN - 1521-3749 VL - 636 IS - 6 SP - 947 EP - 953 ER - TY - GEN A1 - Jahn, Stephan F. A1 - Jakob, Alexander A1 - Blaudeck, Thomas A1 - Schmidt, Peer A1 - Lang, Heinrich A1 - Baumann, Reinhard R. T1 - Inkjet printing of conductive patterns with an aqueous solution of [AgO2C(CH2OCH2)3H] without any additional stabilizing ligands T2 - Thin Solid Films N2 - The use of silver(I)-2-[2-(2-methoxyethoxy)ethoxy]acetate, [AgO2C(CH2OCH2)3H], and its application as an aqueous metal-organic decomposition (MOD) inkjet ink is reported. The chemical and physical properties of the silver carboxylate and the ink formulated thereof are discussed. The ink meets all requirements of piezo driven inkjet printing. The printed features were converted into electrically conducting silver patterns by thermal or photo-thermal treatment. The conversion of [AgO2C(CH2OCH2)3H] to elemental silver follows a two-step decomposition as demonstrated by thermogravimetry–mass spectrometry (TG–MS) measurements. The measured conductivities of the printed features on glass and polyethylene-terephthalate (PET) are 2.7 × 107 S m−1 and 1.1 × 107 S m−1, respectively, which correspond to 43% (glass) and 18% (PET) of the bulk silver conductivity. KW - Inkjet printing KW - Silver KW - Carboxylate KW - Ethyleneglycol KW - Flexible electronics Y1 - 2010 UR - http://www.sciencedirect.com/science/article/pii/S0040609010000866 U6 - https://doi.org/10.1016/j.tsf.2010.01.030 SN - 0040-6090 VL - 518 IS - 12 SP - 3218 EP - 3222 ER -