Horst Borrmann

Publications (26)89.97 Total impact

• Article: Synthesis, crystal structure and physical properties of the clathrate-I phase Ba(8)Rh(x)Si(46-x-y)□(y).

  Walter Jung, Heike Kessens, Alim Ormeci, Walter Schnelle, Ulrich Burkhardt, Horst Borrmann, Hong Duong Nguyen, Michael Baitinger, Yuri Grin
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  ABSTRACT: The new clathrate-I phase Ba(8)Rh(x)Si(46-x-y)□(y) (2.36 < x < 2.74; y = 0.65 for x = 2.74), Pearson symbol cP54, space group Pm3[combining macron]n, was prepared as a single phase and characterized. For these compositions, the lattice parameter does not change significantly and was found to be a = 10.347(1) Å. Phase relations were investigated by means of metallographic and thermal analyses. The incongruently melting phase Ba(8)Rh(x)Si(46-x-y)□(y) was obtained by annealing a solidified melt of the stoichiometric composition at 1000 °C for five days. Below 850 °C, the clathrate phase slowly decomposes to BaSi(2), Si and the new compound BaRh(2)Si(9). Crystal structure and vacancy concentration were investigated by means of single crystal and powder X-ray diffraction and wavelength dispersive X-ray spectroscopy analyses. Quantum chemical calculations show that the Rh 4d states hybridize with Si 3p states so that the DOS structure cannot be simply deduced in a rigid band approach from that of the binary Ba(8)Si(46). Analysis of the chemical bonding applying the ELI-D approach yielded covalent two-center two-electron bonds between Rh and Si atoms. For the composition Ba(8)Rh(2.74)Si(42.61)□(0.65), a temperature dependent diamagnetic susceptibility and an almost temperature independent electrical resistivity (ρ ≈ 5 μΩm) were observed. The magnitude of the negative Seebeck coefficient is increasing linearly with temperature from 0 μV K(-1) at 2 K to -35 μV K(-1) at 850 K indicating n-type electrical conductivity.
  Dalton Transactions 10/2012; · 3.84 Impact Factor
• Article: A clathrate-I phase with Li-Ge framework.

  Ying Liang, Bodo Böhme, Alim Ormeci, Horst Borrmann, Oliver Pecher, Frank Haarmann, Walter Schnelle, Michael Baitinger, Yuri Grin
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  ABSTRACT: A clathrate containing lithium: K(8) Li(x) Ge(44-x/4) □(2-3x/4) constitutes the first intermetallic clathrate-I containing lithium. Different to the clathrate phases formed with other alkali metals, Li does not occupy positions within the polyhedral cages but substitutes Ge in the host framework.
  Chemistry 07/2012; 18(32):9818-22. · 5.93 Impact Factor
• Article: TM7TM'6B8 (TM = Ta, Nb; TM' = Ru, Rh, Ir): new compounds with [B6] ring polyanions.

  Qiang Zheng, Miroslav Kohout, Roman Gumeniuk, Nikolay Abramchuk, Horst Borrmann, Yurii Prots, Ulrich Burkhardt, Walter Schnelle, Lev Akselrud, Hui Gu, Andreas Leithe-Jasper, Yuri Grin
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  ABSTRACT: The ternary boron compounds TM(7)TM'(6)B(8) (TM = Ta, Nb; TM' = Ru, Rh, Ir) were prepared by high-temperature thermal treatment of mixtures of the elements. An analysis of the chemical bonding by the electron density/electron localizability approach reveals formation of covalently bonded polyanions [B(6)] and [TM'(6)B(2)]. The cationic part of the structure contains separated TM cations. In agreement with the chemical bonding analysis and band structure calculations, all TM(7)TM'(6)B(8) compounds are metallic Pauli-paramagnets (TM' = Ru, Rh) or diamagnets (TM' = Ir).
  Inorganic Chemistry 06/2012; 51(14):7472-83. · 4.60 Impact Factor
• Article: Atomic interactions in the p-type clathrate I Ba8Au5.3Ge40.7.

  Hui Zhang, Horst Borrmann, Niels Oeschler, Christophe Candolfi, Walter Schnelle, Marcus Schmidt, Ulrich Burkhardt, Michael Baitinger, Jing-Tai Zhao, Yuri Grin
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  ABSTRACT: Single crystals of Ba(8)Au(5.3)Ge(40.7) [space group Pm(3)n (No. 223), a = 10.79891(8) Å] were prepared by a Bridgman technique. The crystal structure refinement based on single-crystal X-ray diffraction data does not reveal any vacancies in the Au/Ge framework or in the cages. In addition to the ionic bonding between Ba and the anionic framework, a direct interaction between Ba and Au atoms was identified in Ba(8)Au(5.3)Ge(40.7) by applying the electron localizability indicator. As expected by the chemical-bonding picture, Ba(8)Au(5.3)Ge(40.7) is a diamagnet and shows p-type electrical conductivity with a hole carrier concentration of 7.14 × 10(19) cm(-3) at 300 K and very low lattice thermal conductivity of ≈0.6 W m(-1) K(-1) at 500 K. The thermoelectric figure of merit ZT of single crystals of Ba(8)Au(5.3)Ge(40.7) attains 0.3 at 511 K and reaches 0.9 at 680 K in a polycrystalline sample of closely similar composition. This opens up an opportunity for tuning of the thermoelectric properties of materials in the Ba-Au-Ge clathrate system by changing the chemical composition.
  Inorganic Chemistry 02/2011; 50(4):1250-7. · 4.60 Impact Factor
• Source

  Available from: cmu.edu

  Article: Planar Fe6 cluster units in the crystal structure of RE15Fe8C25 (RE=Y, Dy, Ho, Er).

  Bambar Davaasuren, Horst Borrmann, Enkhtsetseg Dashjav, Guido Kreiner, Michael Widom, Walter Schnelle, Frank R Wagner, Rüdiger Kniep
  Angewandte Chemie International Edition 08/2010; 49(33):5688-92. · 13.45 Impact Factor
• Article: Preparation and crystal growth of Na24Si136.

  Matt Beekman, Michael Baitinger, Horst Borrmann, Walter Schnelle, Katrin Meier, George S Nolas, Yuri Grin
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  ABSTRACT: The synthesis and single crystal growth of clathrate-II Na(24)Si(136) is performed in one step applying the spark plasma treatment to the precursor Na(4)Si(4). The reported results demonstrate a new route to intermetallic compounds facilitated by the electric field and current. SPS is revealed to offer significant opportunities as a novel preparatory method for synthesis and crystal growth of solid state materials.
  Journal of the American Chemical Society 08/2009; 131(28):9642-3. · 9.91 Impact Factor
• Source

  Available from: mpg.de

  Article: Electronic structure, chemical bonding, and solid-state NMR spectroscopy of the digallides of Ca, Sr, and Ba.

  Frank Haarmann, Katrin Koch, Daniel Grüner, Walter Schnelle, Oliver Pecher, Raul Cardoso-Gil, Horst Borrmann, Helge Rosner, Yuri Grin
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  ABSTRACT: Combined application of (69,71)Ga NMR spectroscopy and quantum mechanical calculations reveals the chemical bonding in the digallides of Ca, Sr, and Ba. An analysis of the electron localization function (ELF) shows honeycomb-like 6(3) nets of the Ga atoms as the most prominent structural features in SrGa(2) and BaGa(2). For CaGa(2) a description of a 3+1-coordinated Ga atom is revealed by the ELF and by an analysis of interatomic distances. The NMR spectroscopic signal shift is mainly due to the Knight shift and is almost equal for the investigated digallides, whereas the anisotropy of the signal shift decreases with the radius of the alkaline-earth metals. Calculated and observed values of the electric field gradient (EFG) are in good agreement for CaGa(2) and BaGa(2) but differ by about 21 % for SrGa(2) indicating structural instability. Better agreement is achieved by considering a puckering of the Ga layers. For BaGa(2) an instability of the structure is indicated by a peak in the density of states at the Fermi level, which is shifted to lower energies when taking puckering of the Ga layers into account. Both structural modifications are confirmed by crystallographic information. The Fermi velocity of the electrons is strongly anisotropic and is largest in the (001) plane of the crystal structure. This results in an alignment of the crystallites with the [001] axis perpendicular to the magnetic field as observed in (69,71)Ga NMR spectroscopy and magnetic susceptibility experiments. The electron transport is predominantly mediated by the Ga-Ga p(x)- and p(y)-like electrons in the (001) plane. The specific heat capacity of BaGa(2) was determined and indicated the absence of phase transitions between 1.8 and 320 K.
  Chemistry 02/2009; 15(7):1673-84. · 5.93 Impact Factor
• Article: Templated synthesis of mesolamellar n-alkylamine borophosphates.

  Shuang Chen, Horst Borrmann, Ya-Xi Huang, Zhi-Jun Zhang, Hao-Hong Chen, Jing-Tai Zhao
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  ABSTRACT: A family of lamellar mesostructured n-alkylamine borophosphates, denoted C n A-BPO (BPO stands for inorganic borophosphate layer; n = 9-15, the number of carbon atoms in the n-alkylamine chain) has been prepared hydrothermally at 160 degrees C by using neutral n-alkylamines as templates. Those C n A-BPO compounds were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric measurements, and differential thermal analysis (TG-DTA) as well as chemical analyses. Interestingly, these compounds may form a bilayer, a monolayer, or mixed state of bilayer and monolayer structures depending on the content of n-alkylamine. Linear relationships for both bilayer and monolayer compounds were observed between the interlayer distances and the numbers of carbon atoms in the n-alkylamine chain. The thickness of the inorganic layers, the arrangement of n-alkylamine in the interlayer space, and the composition of the compounds are proposed.
  Langmuir 09/2008; 24(17):9323-7. · 4.19 Impact Factor
• Article: The Metallic Zintl Phase Ba3Si4 – Synthesis, Crystal Structure, Chemical Bonding, and Physical Properties

  Umut Aydemir, Alim Ormeci, Horst Borrmann, Bodo Böhme, Fabio Zürcher, Burcu Uslu, Thorsten Goebel, Walter Schnelle, Paul Simon, Wilder Carrillo-Cabrera, Frank Haarmann, Michael Baitinger, Reinhard Nesper, Hans Georg von Schnering, Yuri Grin Prof. Dr
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  ABSTRACT: The Zintl phase Ba3Si4 has been synthesized from the elements at 1273 K as a single phase. No homogeneity range has been found. The compound decomposes peritectically at 1307(5) K to BaSi2 and melt. The butterfly-shaped Si46− Zintl anion in the crystal structure of Ba3Si4 (Pearson symbol tP28, space group P42/mnm, a = 8.5233(3) Å, c = 11.8322(6) Å) shows only slightly different Si-Si bond lengths of d(Si–Si) = 2.4183(6) Å (1×) and 2.4254(3) Å (4×). The compound is diamagnetic with χ ≈ −50 × 10−6 cm3 mol−1. DC resistivity measurements show a high electrical resistivity (ρ(300 K) ≈ 1.2 × 10−3 Ω m) with positive temperature gradient dρ/dT. The temperature dependence of the isotropic signal shift and the spin-lattice relaxation times in 29Si NMR spectroscopy confirms the metallic behavior. The experimental results are in accordance with the calculated electronic band structure, which indicates a metal with a low density of states at the Fermi level. The electron localization function (ELF) is used for analysis of chemical bonding. The reaction of solid Ba3Si4 with gaseous HCl leads to the oxidation of the Si46− Zintl anion and yields nanoporous silicon.
  Zeitschrift für anorganische Chemie 07/2008; 634(10):1651 - 1661.
• Article: The first silicon-based cationic clathrate III with high thermal stability: Si172-xPxTey (x=2y, y>20).

  Julia V Zaikina, Kirill A Kovnir, Frank Haarmann, Walter Schnelle, Ulrich Burkhardt, Horst Borrmann, Ulrich Schwarz, Yuri Grin, Andrei V Shevelkov
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  ABSTRACT: A new representative of a very rare clathrate III family, Si130P42Te21, has been synthesized from the elements. It crystallizes in the tetragonal space group P4(2)/mnm (no. 136) with the unit cell parameters a=19.2632(3) angstroms, c=10.0706(2) angstroms. Single crystal X-ray diffraction and solid state 31P NMR revealed a non-random distribution of phosphorus atoms over the framework positions. The crystal structure features a peculiar packing of large polyhedra Te@(Si/P)(n) never observed before for cationic clathrates. Despite the structural complexity, the composition of the novel clathrate Is in accordance with the Zintl rule, which was confirmed by a combination of optical metallography, scanning electron microscopy (SEM) and wavelength dispersive X-ray spectroscopy (WDXS), as well as by diamagnetic and semiconducting behavior of the synthesized phase. Clathrate Si130P42Te21 exhibits the highest reported thermal stability for this class of materials, it decomposes at 1510 K. This opens new perspectives for the creation of clathrate-based materials for high-temperature applications.
  Chemistry 07/2008; 14(18):5414-22. · 5.93 Impact Factor
• Article: Crystal structure and local order in Co(6)Al(11-x)Si(6+x).

  Klaus W Richter, Yurii Prots, Horst Borrmann, Reiner Ramlau, Yuri Grin
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  ABSTRACT: The ternary compound Co(6)Al(11-x)Si(6+x) (epsilon phase) was prepared from the elements by arc melting and subsequent heat treatment, and then characterized by single-crystal X-ray diffraction (XRD), electron-probe microanalysis (EPMA), differential thermal analysis (DTA) and transmission electron microscopy (TEM). This new structure type consists of planar layers with the composition [Co(6)Al(10)Si(4)], which are penetrated by perpendicular (Si-Si-Al) chains. While the layers are well described by an orthorhombic model (space group Pnma, Pearson symbol oP46), the chains exhibit doubled periodicity, thus yielding a superstructure. Two alternative ordering models (space group Cmc2(1), oC184, and space group P2(1)/c, mP92) are presented and discussed based on XRD and TEM results. The (Si-Si-Al) chains are located in pentagonal antiprismatic ;channels' which reveal the similarity of the Co(6)Al(11-x)Si(6+x) structure to Al-rich transition-metal compounds such as Co(4)Al(13), Co(2)Al(5), Fe(4)Al(13), V(7)Al(45), V(4)Al(23) and VAl(10), which also exhibit this type of pentagonal ;channels' in their crystal structures. The phase shows only a very small homogeneity range.
  Acta Crystallographica Section B Structural Science 09/2007; 63(Pt 4):551-60. · 2.29 Impact Factor
• Article: K7B7Si39, ein Borosilicid mit Clathrat‐I‐Struktur

  Walter Jung Prof. Dr, Josef Lörincz, Reiner Ramlau, Horst Borrmann, Yurii Prots, Frank Haarmann, Walter Schnelle, Ulrich Burkhardt, Michael Baitinger, Yuri Grin Prof. Dr
  Angewandte Chemie 08/2007; 119(35):6846 - 6850.
• Article: Control of channel shapes in a microporous manganese(II)-borophosphate framework by variation of size and shape of organic template cations.

  Ya-Xi Huang, Oliver Hochrein, Dirk Zahn, Yurii Prots, Horst Borrmann, Rüdiger Kniep
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  ABSTRACT: The templated microporous compounds [H2(Templ.)][MnII{B2P3O12(OH)}], [templates: 1,3-diaminopropane, C3H10N2 (DAP); piperazine, C4H10N2 (PIP); 1,4-diazacyclo[2.2.2]octane, C6H12N2 (DABCO)] were prepared under mild hydrothermal conditions. The crystal structures (H2DAP-Mn: Pmc2(1) (no. 26), a=1259.43(5), b=949.86(5), c=1135.92(5) pm, Z=4; H2PIP-Mn: Ima2 (no. 46), a=1257.9(1), b=948.69(8), c=1158.19(8) pm, Z=4; H2DABCO-H2PIP-Mn: Ima2 (no. 46), a=1262.90(7), b=961.05(5), c=1151.42(7) pm, Z=4) are characterized by identical framework connectivities [MnII{B2P3O12(OH)}]2-, but vary in shapes (diameters) of the structural channels depending on the shapes of the templating molecule ions. The situation clearly reflects the directing effect of true templates during endotemplating reactions. The experimental results (preparation, chemical analyses, and X-ray refinements) are supported by detailed ab initio calculations (structure optimizations).
  Chemistry 02/2007; 13(6):1737-45. · 5.93 Impact Factor
• Article: K7B7Si39, a borosilicide with the clathrate I structure.

  Walter Jung, Josef Lörincz, Reiner Ramlau, Horst Borrmann, Yurii Prots, Frank Haarmann, Walter Schnelle, Ulrich Burkhardt, Michael Baitinger, Yuri Grin
  Angewandte Chemie International Edition 02/2007; 46(35):6725-8. · 13.45 Impact Factor
• Source

  Available from: mpg.de

  Article: Metal-metal bonding in sterically frustrated dipalladium species.

  Stefan Deeken, Günter Motz, Viktor Bezugly, Horst Borrmann, Frank R Wagner, Rhett Kempe
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  ABSTRACT: Stoichiometric-deficient lithiation of (2,6-diisopropylphenyl)(4-methylpyridin-2-yl)amine and reaction with [(cod)PdCl2] (cod = 1,5-cyclooctadiene) yield a dimeric Pd complex. X-ray structural analysis of this complex reveals a very short Pd-Pd distance (2.429 A). Topological analysis of the electron density and the electron localization function from scalar relativistic density functional theory calculations clearly indicate a Pd(I)-Pd(I) sigma-bonding interaction, for which the corresponding occupied localized orbital can be identified.
  Inorganic Chemistry 12/2006; 45(23):9160-2. · 4.60 Impact Factor
• Article: Zum chemischen Transport von Seltenerdvanadaten(V)

  Marcus Schmidt Dr, Reiner Ramlau, Walter Schnelle, Horst Borrmann, Edgar Milke, Michael Binnewies
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  ABSTRACT: Kristalle der Seltenerdvanadate(V) SEVO4 (SE = Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho) sowie ausgewählte Mischkristalle wurden durch endothermen chemischen Transport mit TeCl4 als Transportmittel erhalten. Die Untersuchung zur Zusammensetzung der Gasphase erfolgte massenspektrometrisch. Für NdVO4 und TbVO4 wurden die magnetischen Eigenschaften untersucht und aus Messungen der Wärmekapazität die Standardentropien und -enthalpien ermittelt.Chemical Vapour Transport of Rare-Earth Vanadates(V)Crystals of a series of rare-earth vanadates(V) REVO4 (RE = Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho) and mixed crystals of selected composition were obtained by endothermic chemical transport with TeCl4 as a transport medium. The gaseous phase of the transport reaction has been studied using mass spectrometry. For NdVO4 and TbVO4 the magnetic properties were investigated, standard entropies and enthalpies were derived from specific heat measurements.
  Zeitschrift für anorganische Chemie 02/2005; 631(2‐3):284 - 292.
• Source

  Available from: xray-crystal.com

  Article: Synthesis, Magnetism, and Crystal Structure of Li2Fe[(PO4)(HPO4)] and its Hydrogen Position Refinement

  Jin-Xiao Mi, Horst Borrmann, Hui Zhang, Ya-Xi Huang, Walter Schnelle, Jing-Tai Zhao Prof. Dr, Rüdiger Kniep
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  ABSTRACT: Lithium iron(III) monophosphate-monohydrogen-monophosphate, Li2Fe[(PO4)(HPO4)], was synthesized under mild hydrothermal conditions and its crystal structure was determined by single crystal X-ray diffraction methods. Crystallographic data: monoclinic, P121/n1 (no. 14), a = 4.8142(2) Å, b = 7.9898(4) Å, c = 7.4868(4) Å, β = 104.398(3)°, V = 278.93(2) Å3, Z = 2, Dx = 3.104 g · cm-3. The structure is characterized by FeO6 octahedra sharing common O-corners with six neighbouring PO4 tetrahedra to form a three-dimensional framework. Lithium cations are located within channels running along [100]. The channels are formed by eight-membered rings resulting from the connection of alternating FeO6 octahedra (4×) and phosphate tetrahedra (4×). High-resolution diffraction data allowed to refine a split model for the position of the hydrogen atom. Magnetization data confirm the valence state 3+ for iron and detect an antiferromagnetic ordering of the iron moments below 23.6 K. Thermal decomposition of the compound was investigated by DTA/TG methods.Synthese, Magnetismus und Kristallstruktur von Li2Fe[(PO4)(HPO4)] mit Verfeinerung der Position des WasserstoffatomsLithium-Eisen(III)-monophosphat-monohydrogenphosphat, Li2Fe[(PO4)(HPO4)], wurde unter milden hydrothermalen Bedingungen dargestellt und die Kristallstruktur durch Röntgenbeugung am Einkristall bestimmt. Kristallographische Daten: monoklin, P121/n1 (Nr. 14), a = 4, 8142(2) Å, b = 7, 9898(4) Å, c = 7, 4868(4) Å, β = 104, 398(3)°, V = 278, 93(2) Å3, Z = 2, Dx = 3, 104 g · cm-3. Die Struktur ist durch FeO6-Koordinationsoktaeder charakterisiert, die über gemeinsame Ecken mit sechs benachbarten PO4-Tetraedern zu einem dreidimensionalen Netzwerk verknüpft sind. Die Lithium-Kationen befinden sich in entlang [100] verlaufenden Kanälen. Der Durchmesser der Kanäle wird durch achtgliedrige Ringe bestimmt, die aus der alternierenden Verknüpfung von FeO6-Oktaedern (4×) und PO4-Tetraedern (4×) resultieren. Die zu hohen Beugungswinkeln gemessenen Röntgendaten erlauben die Verfeinerung eines Splitmodells für die Position des Wasserstoffatoms. Messungen der magnetischen Suszeptibilität bestätigen die Oxidationsstufe 3+ für Eisen und zeigen antiferromagnetische Ordnung der Momente des Eisens unterhalb von 23, 6 K. Der thermische Abbau der Verbindung wurde mit DTA/TG-Methoden verfolgt.
  Zeitschrift für anorganische Chemie 08/2004; 630(11):1632 - 1636.
• Article: Mg2[BN2]Cl and Mg8[BN2]5I: Novel Magnesium Nitridoborate Halides — Syntheses, Crystal Structures, and Vibrational Spectra

  Mehmet Somer Prof, Mehmet Nuri Kütükcü, Raul Cardoso Gil, Horst Borrmann, Wilder Carrillo-Cabrera
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  ABSTRACT: The title compounds have been synthesized at 1473 K from stoichiometric mixtures of the binary components Mg3N2, MgX2 (X = Cl, I) and BN in arc-welded steel ampoules encapsulated in evacuated silica tubes. Mg2[BN2]Cl (1) and Mg8[BN2]5I (2) crystallize in the orthorhombic space groups Pbca (no. 61) and Imma (no. 74), respectively, with a = 6.6139(8)Å, b = 9.766(1)Å, c = 10.600(1)Å, Z = 8 for 1 and a = 13.535(3)Å, b = 9.350(2)Å, c = 11.194(2)Å, Z = 4 for 2. The crystal structures are characterized mainly by Mg6 trigonal prisms which are condensed to 3D frameworks in different ways. Part of the trigonal prisms are centered by the [N—B—N]3— anions and other voids in the framework by the X— anions. The magnesium environment around Cl— is a very distorted monocapped trigonal prism (CN = 6+1) and that of I— is a bicapped heptagonal prism (CN = 14+2). The bond lengths and bond angles for the relevant [BN2]3— anions are d(B—N) = 1.330 — 1.338Å, ∠N—B—N = 175.8° in 1 and d(B—N) = 1.330 — 1.339Å, ∠N—B—N = 176.8° — 178.0° in 2.The vibrational spectra of the title compounds have been recorded and interpreted based on the D∞h symmetry of the relevant [N—B—N]3— groups considering the site symmetry splitting.Mg2[BN2]Cl und Mg8[BN2]5I: Neuartige Magnesium-Nitridoborat-Halogenide — Darstellung, Kristallstrukturen und SchwingungsspektrenDie Titelverbindungen wurden ausgehend von stöchiometrischen Gemengen der binren Komponenten Mg3N2, MgX2 (X = Cl, I) und BN in verschweißten Stahlampullen (Schutzrohr: evakuiertes Quarzglasrohr) bei 1473 K synthetisiert. Mg2[BN2]Cl (1) und Mg8[BN2]5I (2) kristallisieren in den orthorhombischen Raumgruppen Pbca (Nr. 61) und Imma (Nr. 74), mit a = 6.6139(8)Å, b = 9.766(1)Å, c = 10.600(1)Å, Z = 8 (1) bzw. a = 13.535(3)Å, b = 9.350(2)Å, c = 11.194(2)Å, Z = 4 (2). Die Kristallstrukturen sind durch die trigonalen Prismen Mg6 geprgt, die auf unterschiedliche Arten zu einem 3D-Gerüst kondensiert sind. Die Anionen [N—B—N]3— und X— zentrieren hierbei einen Teil der trigonalen Prismen bzw. Lücken im 3D-Gerüst. Die Magnesium-Umgebung der Halogenidionen Cl— und I— kann jeweils als ein verzerrtes, einfach überkapptes, trigonales Prisma (CN = 6+1) bzw. als ein zweifach überkapptes, heptagonales Prisma (CN = 14+2) beschrieben werden. Die Bindungslngen und -winkel für die [N—B—N]3—-Anionen sind d(B—N) = 1.330 — 1.338Å, ∠N—B—N = 175.8° (1) bzw. d(B—N) = 1.330 — 1.339Å, ∠N—B—N = 176.8 — 178.0° (2).Die Schwingungspektren der Titelverbindungen wurden aufgenommen und auf der Basis der D∞h Symmetrie einer diskreten [BN2]3— Einheit unter Berücksichtigung der Site-Symmetrie Aufspaltung interpretiert.
  Zeitschrift für anorganische Chemie 06/2004; 630(7):1015 - 1021.
• Article: (C6H14N2){Zn[ZnB2P4O15(OH)2]·(C6H13N2)Cl}:  A New Templated Zincoborophosphate

  Ya-Xi Huang, Gerd Schäfer, Wilder Carrillo-Cabrera, Horst Borrmann, Raul Cardoso Gil, Rüdiger Kniep
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  ABSTRACT: Colorless crystals of (C6H14N2){Zn[ZnB2P4O15(OH)2]·(C6H13N2)Cl} (1) were prepared from mixtures of ZnCl2, B2O3, diaza-bicyclo[2.2.2]octane (DABCO), and 85% H3PO4 under mild hydrothermal conditions (170 °C). The crystal structure was determined by single-crystal X-ray diffraction (monoclinic, P21/c (No. 14), a = 1704.3(1) pm, b = 937.03(5) pm, c = 1619.75(8) pm, β = 96.894(3)°, Z = 2). The crystal structure contains tetrahedral zigzag ribbons, {[ZnB2P4O15(OH)2]4-}, running along [010]. Additional ZnO2NCl tetrahedra at the borders complete the ribbons by sharing common O-corners with the zincoborophosphate polymer. The nitrogen atoms of the quaternary ZnO2NCl tetrahedra belong to monoprotonated (HDABCO)+ ions. A second (diprotonated) species, (H2DABCO)2+, acts as a pure template and is fixed to adjacent zincoborophosphate ribbons along [100] via hydrogen bonds. The title compound 1 can be described as an adduct of (C6H14N2){Zn[ZnB2P4O15(OH)2]} with diaza-bicyclo[2.2.2]octane-hydrochloride. Thermoanalytical and X-ray powder diffraction investigations to high temperatures (740 °C) show the decomposition of 1 and the formation of a NH4[ZnBP2O8] polymorph as an intermediate.
  11/2003;
• Article: MII(C4H12N2)[B2P3O12(OH)] (MII = Co, Zn): Synthesis and Crystal Structure of Novel Open Framework Borophosphates

  Gerd Schäfer, Horst Borrmann, Rüdiger Kniep Prof. Dr
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  ABSTRACT: Two novel borophosphates, MII(C4H12N2)[B2P3O12(OH)] (MII = Co, Zn), exhibiting open frameworks, have been synthesized by hydrothermal reactions (T = 165 °C). The crystal structures of the isotypic compounds have been determined both at 293 K (orthorhombic, Ima2 (no. 46), Z = 4; MII = Co: a = 12.4635(4) Å, b = 9.4021(4) Å, c = 11.4513(5) Å, V = 1341.90 Å3, R1 = 0.0202, wR2 = 0.0452, 2225 observed reflections with I > 2σ(I); MII = Zn: a = 12.4110(9) Å, b = 9.4550(5) Å, c = 11.4592(4) Å, V = 1344.69 Å3, R1 = 0.0621, wR2 = 0.0926, 1497 observed reflections with I > 2σ(I)). Distorted CoO6-octahedra and ZnO5-square-pyramids, respectively, share common oxygen-corners with BO4-, PO4- and (HO)PO3-tetrahedra. The tetrahedral groups are linked via common corners to form infinite loop-branched borophosphate chains [B2P3O12(OH)4–]. The open framework of MII-coordination polyhedra and tetrahedral borophosphate chains contains a three-dimensional system of interconnected structural channels running along [100], [011] and [011], respectively, which are occupied by di-protonated piperazinium ions.MII(C4H12N2)[B2P3O12(OH)] (MII = Co, Zn): Darstellung und Kristallstrukturen neuer Borophosphate mit offenen GerüststrukturenZwei neue Borophosphate mit offenen Gerüststrukturen, MII(C4H12N2)[B2P3O12(OH)] (MII = Co, Zn), wurden unter hydrothermalen Bedingungen (T = 165 °C) dargestellt. Die Kristallstrukturen der isotypen Verbindungen (Einkristallmethoden; orthorhombisch, Ima2 (Nr. 46), Z = 4; MII = Co: a = 12,4635(4) Å, b = 9,4021(4) Å, c = 11,4513(5) Å, V = 1341,90 Å3, R1 = 0,0202, wR2 = 0,0452, 2225 beobachtete Reflexe mit I > 2σ(I); MII = Zn: a = 12,4110(9) Å, b = 9,4550(5) Å, c = 11,4592(4) Å, V = 1344,69 Å3, R1 = 0,0621, wR2 = 0,0926, 1497 beobachtete Reflexe mit I > 2σ(I)) enthalten verzerrte CoO6-Oktaeder bzw. quadratische ZnO5-Pyramiden, die über gemeinsame Sauerstoff-Ecken mit BO4-, PO4- und (HO)PO3-Tetraedern verknüpft sind. Die Tetraedergruppen bilden durch Kondensation über gemeinsame Ecken unendliche, zyklisch verzweigte Borophosphat-Ketten [B2P3O12(OH)4–]. Die insgesamt offene Gerüststruktur aus MII-Koordinationspolyedern und Borophosphat-Ketten ist von einem dreidimensionalen System unterschiedlicher Struktur-Kanäle durchzogen, die entlang [100] bzw. [011] und [011] verlaufen und mit zweifach protonierten Piperazinium-Ionen besetzt sind.
  Zeitschrift für anorganische Chemie 03/2001; 627(1):61 - 67.