@misc{EcksteinHohmannWeihrichetal., author = {Eckstein, Nadine and Hohmann, Andrea and Weihrich, Richard and Nilges, Tom and Schmidt, Peer}, title = {Synthesis and Phase Relations of Single-Phase Fibrous Phosphorus}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {Vol. 639}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {15}, issn = {1521-3749}, doi = {10.1002/zaac.201300327}, pages = {2741 -- 2743}, abstract = {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.}, language = {en} } @misc{BawohlNilgesSchmidt, author = {Bawohl, Melanie and Nilges, Tom and Schmidt, Peer}, title = {Temperature Initiated P-Polymerization in Solid [Cd3Cu]CuP10}, series = {Inorganic chemistry}, volume = {52}, journal = {Inorganic chemistry}, number = {20}, issn = {1520-510X}, doi = {10.1021/ic401508n}, pages = {11895 -- 11901}, abstract = {[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.}, language = {en} } @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{BachhuberAppenDronskowskietal., author = {Bachhuber, Frederik and Appen, J{\"o}rg von and Dronskowski, Richard and Schmidt, Peer and Nilges, Tom and Pfitzner, Arno and Weihrich, Richard}, title = {Van der Waals interactions in selected allotropes of phosphorus}, series = {Zeitschrift f{\"u}r Kristallografie}, volume = {230}, journal = {Zeitschrift f{\"u}r Kristallografie}, number = {2}, issn = {2196-7105}, doi = {10.1515/zkri-2014-1800}, pages = {107 -- 115}, abstract = {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.}, language = {en} } @misc{BachhuberAppenDronskowskietal., author = {Bachhuber, Frederik and Appen, J{\"o}rg von and Dronskowski, Richard and Schmidt, Peer and Nilges, Tom and Pfitzner, Arno and Weihrich, Richard}, title = {The Extended Stability Range of Phosphorus Allotropes}, series = {Angewandte Chemie / International edition}, volume = {53}, journal = {Angewandte Chemie / International edition}, number = {43}, issn = {1521-3773}, doi = {10.1002/anie.201404147}, pages = {11629 -- 11633}, abstract = {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.}, 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{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{PfisterSchaeferOttetal., author = {Pfister, Daniela and Sch{\"a}fer, Konrad and Ott, Claudia and Gerke, Birgit and P{\"o}ttgen, Rainer and Janka, Oliver and Baumgartner, Maximilian and Efimova, Anastasia and Hohmann, Andrea and Schmidt, Peer and Venkatachalam, Sabarinathan and W{\"u}llen, Leo van and Sch{\"u}rmann, Ulrich and Kienle, Lorenz and Duppel, Viola and Parzinger, Eric and Miller, Bastian and Becker, Jonathan and Holleitner, Alexander and Weihrich, Richard and Nilges, Tom}, title = {Inorganic double helices in semiconducting SnIP}, series = {Advanced Materials}, volume = {28}, journal = {Advanced Materials}, number = {44}, issn = {1521-4095}, doi = {10.1002/adma.201603135}, pages = {9783 -- 9791}, abstract = {SnIP is the first atomic-scale double helical semiconductor featuring a 1.86 eV bandgap, high structural and mechanical flexibility, and reasonable thermal stability up to 600 K. It is accessible on a gram scale and consists of a racemic mixture of right- and left-handed double helices composed by [SnI] and [P] helices. SnIP nanorods <20 nm in diameter can be accessed mechanically and chemically within minutes.}, 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{SchmidtHohmannNilgesetal., author = {Schmidt, Peer and Hohmann, Andrea and Nilges, Tom and K{\"o}pf, Marianne and Weihrich, Richard}, title = {Synthesis of Element Allotropes of Arsenic and Phosphorus by Application of Electromotive Series of Solids}, series = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, volume = {640}, journal = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, number = {11}, issn = {1521-3749}, doi = {10.1002/zaac.201490026}, pages = {2386}, abstract = {Calculation of electromotive series of solids allows easy prediction of reaction pathways[1]. Using the electromotive series of systems As-P-O and As-P-X (X = F, Cl, Br, I) the formation of element allotropes via the oxide and halide compounds in thermite type reactions can be deduced: phosphorous will reduce the arsenic oxides to elemental arsenic, forming grey or black allotrope, depending on reaction mixture composition.}, 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{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} } @incollection{NilgesSchmidtWeihrich, author = {Nilges, Tom and Schmidt, Peer and Weihrich, Richard}, title = {Phosphorus: The Allotropes, Stability, Synthesis, and Selected Applications}, series = {Encyclopedia of Inorganic and Bioinorganic Chemistry}, booktitle = {Encyclopedia of Inorganic and Bioinorganic Chemistry}, editor = {Scott, Robert A.}, edition = {2. Auflage}, publisher = {John Wiley Sons}, address = {Hoboken, US}, isbn = {978-1-119-95143-8}, doi = {10.1002/9781119951438.eibc2643}, pages = {1 -- 19}, abstract = {Phosphorus, first found in the seventeenth century, played an important role in the definition of the element term by Lavoisier and thus shaped the beginning of the era of modern chemistry. It was discovered for the first time in the most unstable crystalline modification—the white phosphorus. Today, a variety of experimentally proven allotropes are known. The most common allotropes, such as black, violet, and fibrous phosphorus, are described here with respect to their synthesis, crystal structures, thermal, and thermodynamic properties. Besides, more than 50 crystalline allotropes have been predicted, and their stabilities have been estimated using quantum-chemical methods. This way, phosphorus becomes one of the most structurally variable elements of the periodic table. In this article, some of the most reasonable and sophisticated calculations are presented. The applications of elemental phosphorus are mainly connected with its semiconducting properties. Thus, the development of current applications is strongly related to new synthesis methods for direct preparation of individual, phase pure allotropic forms of phosphorus. The past decade supplied basic results on the formation of black phosphorus and other modifications, primarily using the mineralizer concept. Related to graphene and other two-dimensional, layered structures, phosphorene is of drastically rising interest. The pertinent modifications are characterized by corrugated arrangement of six-membered P-rings, where both the boat conformation and the chair conformation are known. The application of phosphorene is in a jumping evolution. Currently, phosphorene is already in use in manifold ways, including as a sensor, optical device, transistor, energy-conversion material, and supercapacitor material.}, language = {en} } @misc{PielnhoferBachhuberSchmidtetal., author = {Pielnhofer, Florian and Bachhuber, Frederik and Schmidt, Peer and Nilges, Tom and Weihrich, Richard}, title = {Mit DFT-Modellierungen zu neuen Polyanionenverbindungen}, 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.201204137}, pages = {S. 1634}, abstract = {Verbindungen mit ionischen Baueinheiten erweisen sich als geeignete Materialien zur Energie- und Ressourcennutzung. Beispiele sind Li-Elektrodenmaterialien oder neue Thermoelektrika, die aufgrund ihrer Teilstrukturen schaltbar werden. Das Design neuer funktionaler Materialien verlangt dabei nach einem grundlegenden Verst{\"a}ndnis von Struktur-Eigenschafts-Beziehungen, metastabilen Strukturen und Umwandlungen. Dies bedarf des Einsatzes kombinierter experimenteller und theoretischer Methoden. Zur systematischen Erforschung metastabiler Strukturen wurde j{\"u}ngst das Konzept der Strukturvorhersage in Energielandschaften mit ab initio Methoden auf das System P1-xAsx angewandt und mit experimentellen Messungen verkn{\"u}pft. Im n{\"a}chsten Schritt wurden Verbindungen mit ionischen Teilstrukturen des As, Sb, Se und Te untersucht. Modellhaft wurden nun Zintl-Systemen wie IrPTe und PtSnTe neue m{\"o}gliche metastabile Strukturen identifiziert und auf Funktionalisierungen untersucht.}, language = {de} } @misc{NilgesOstersSchmidtetal., author = {Nilges, Tom and Osters, Oliver and Schmidt, Peer and Sch{\"o}neich, Michael and Weihrich, Richard and Bachhuber, Frederik}, title = {Untersuchungen zur Bildung von schwarzem Arsen}, 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.201008019}, pages = {S. 46}, abstract = {Das Mineralisatorkonzept f{\"u}r Polypniktide, basierend auf PbI2 als Mineralisator, wurde erfolgreich zur Synthese der festen L{\"o}sung 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 m{\"o}glich, das Zellvolumen und die Gitterparameter von reinem, schwarzen Arsen abzuleiten. Die Analyse der Phasenbildung basiert auf der Bestimmung der Gleichgewichtsdr{\"u}cke 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).}, language = {de} } @book{SchmidtNilges, author = {Schmidt, Peer and Nilges, Tom}, title = {Allgemeine Chemie, Teil 5: Wissenschaftliches Arbeiten}, publisher = {Springer Spektrum}, address = {Berlin [u.a.]}, isbn = {978-3-662-47539-3}, pages = {37}, abstract = {Prinzipien des wissenschaftlichen Arbeitens und Methodik zur Erstellung von Protokollen, Kurzberichten, Projektberichten und wissenschaftlichen Publikationen}, language = {de} }