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  • 1
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 908-912 
    ISSN: 0044-2313
    Keywords: In[Nb6Cl15] ; Tl[Nb6Cl15] ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese und Kristallstruktur von M[Nb6Cl15] (M = In, Tl): Neue ternäre Niobhalogenide mit verbrückten [Nb6Cl18]4- -ClusternDie neuen ternären Niobchloride M[Nb6Cl15] (M = In, Tl) wurden durch Festkörperreaktionen stöchiometrischer Gemische von NbCl5, Niobmetall und MCl3 bei 720°C dargestellt. Die Kristallstruktur von In[Nb6Cl15] wurde aus Einkristall-Röntgendaten bestimmt und in der orthorhombischen Symmetrie (Raumgruppe Pmma, Z = 4) mit a = 1786.6(1) pm, b = 1345,52(9) pm, c = 929,34(8) pm, R = 0,028, Rw = 0,037, GooF = 1,06 für alle symmetrieunabhängigen 1552 Reflexe verfeinert. Die Gitter-parameter der isotypen Verbindung Tl[Nb6Cl15] wurden aus Röntgen-Pulverdiffraktometerdaten verfeinert: a = 1785,9(2) pm, b = 1347,2(2) pm, c = 930,2(1) pm. Die Struktur besteht aus [Nb6Cl18]4--Clustern, die über terminale Chlorid-Liganden miteinander verbunden sind und zwei Sorten senkrecht zueinander stehender Ketten bilden, Diese Ketten sind über weitere terminale Liganden zu einem dreidimensionalen Netzwerk verbunden. Die In+- und Tl+-Ionen sind zehnfach koordiniert (in Form eines verzerrten zweifach bekappten Würfels), mit acht inneren und zwei äußeren Chlorid-Liganden.
    Notes: New ternary niobium chlorides corresponding to the formula M[Nb6Cl15] (M = In, T1) were synthesized from solid state reactions of NbCl5, niobium metal, and MCl3 at 720°C. The crystal structure of In[Nb6Cl15] was determined from single crystal X-ray diffraction studies. The structure was refined in the orthorhombic symmetry (space group Pmma, Z = 4) with a = 1786.6(1) pm, b = 1345.52(8) pm, c = 929.34(8) pm, RF = 0.028 and Rw = 0.037, GooF = 1.06 for all 1552 unique reflections. The lattice parameters of the isotypic Tl[Nb6Cl15] compound were refined from X-ray powder diffraction data: a = 1785.9(2) pm, b = 1347.2(2) pm, c = 930.2(1) pm. The structure of In[Nb6Cl15] is made up of [Nb6Cl18]4- clusters linked to each other through terminal chloride ligands to form two sets of chains perpendicular to each other. The chains are linked through other terminal ligands to yield a three-dimensional network. The In+ or Tl+ ions are located in a ten coordination site (distorted bicapped cubic geometry) made up of eight inner and two outer chloride ligands.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 262-265 
    ISSN: 0044-2313
    Keywords: Ca3(BN2)2 ; Sr3(BN2)2 ; NaSr4(BN2)3 ; preparation ; structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of Sr3(BN2)2The structure of Sr3(BN2)2 was determined on single-crystal X-ray data collected with a four-circle diffractometer. Sr3(BN2)2 crystallizes in the cubic space group Im3m (no. 229) with a = 764.56(3) pm and Z = 3. The structure contains linear BN3-2 ions with a B—N bond length of 135.8(6) pm. The straight forward synthesis employing metal nitrides plus boron nitride yielded crystalline powders of M3(BN2)2 (M = Ca, Sr) at 1100°C (5 days). Cubic indexing of guinier patterns gave a = 765.8(1) pm for M = Sr and a = 734.7(2) pm for M = Ca. The structure refinement on a single crystal of Sr3(BN2)2 revealed that one strontium site (2a; 0, 0, 0) is occupied by only about 50%. It has been tried to fully occupy this site with an alkali metal (A) to obtain ASr4(BN2)3 (Z = 2). Reactions with A = Na yielded crystalline powders. Cubic indexing of the guinier pattern analogous to that of Sr3(BN2)2 gave a = 754.2(1) pm.
    Notes: Die Struktur von Sr3(BN2)2 wurde anhand von Einkristall-Röntgendaten, die durch Messung an einem Vierkreisdiffraktometer erhalten wurden, bestimmt. Sr3(BN2)2 kristallisiert in der kubischen Raumgruppe Im3m (Nr. 229) mit a = 764,56(3) pm und Z = 3. Die Struktur enthält lineare BN3-2-Ionen mit einer Bindungslänge B—N von 135,8(6) pm. Die gezielte Darstellung aus den Metallnitriden und Bornitrid zu M3(BN2)2 (M = Ca, Sr) bei 1100°C (5 Tage) ergab kristalline Pulver. Kubische Indizierung der Guinierdiagramme gab a = 765,8(1) pm für M = Sr und 734,7(2) pm für M = Ca. Die Strukturverfeinerung an einem Einkristall von Sr3(BN2)2 zeigte, daß eine Strontiumlage (2a; 0,0,0) nur zu etwa 50% besetzt ist. Es wurde versucht, diese Lage mit einem Alkalimetall (A) entsprechend ASr4(BN2)3 (Z = 2) vollständig zu besetzen. Reaktionen mit A = Na ergaben kristalline Pulver, deren Guinierdiagramme analog zu Sr3(BN2)2 kubisch mit a = 754,2(1) pm indiziert werden konnten.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 258-261 
    ISSN: 0044-2313
    Keywords: alkaline-earth dihalides ; Ca3Br2CBN ; Sr3Cl2CBN ; preparation ; structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Synthesis of Alkaline-Earth Dihalides and the Structures of Ca3Br2CBN and Sr3Cl2CBNThe reaction of alkaline-earth carbonates with ammonium chloride or bromide yields alkaline-earth dihalides at relatively low temperatures (300°C). Ca3Br2CBN and Sr3Cl2CBN were synthesized in sealed niobium containers at 950°C from the metal, its dihalide, boron nitride and graphite. The crystal structure of Sr3Cl2CBN was refined from single crystal data. Sr3Cl2CBN crystallizes isotypic with Ca3Cl2CBN in the orthorhombic space group Pnma (No. 62) with a = 1448.4(2) pm b = 405.46(5) pm, c = 1170.0(1) pm. The lattice constants of Ca3Br2CBN and Sr3Cl2CBN were determined by orthorhombic indexing of the powder patterns (Ca3Br2CBN: a = 1444.3(2) pm, b = 390.64(6) pm, c = 1139.2(2) pm; Sr3Cl2CBN: a = 1444.0(4) pm, b = 405.27(8) pm, c = 1167.8(2) pm). There was no success in preparing homologues with Barium.
    Notes: Die Umsetzung von Erdalkalimetallcarbonaten mit Ammoniumchlorid oder Ammoniumbromid liefert bei relativ niedrigen Temperaturen (300°C) Erdalkalimetalldihalogenide. Ca3Br2CBN und Sr3Cl2CBN wurden in verschweißten Niobcontainern bei 950°C aus dem Metall, dessen Dihalogenid sowie Bornitrid und Graphit hergestellt. Die Kristallstruktur von Sr3Cl2CBN wurde mit Einkristalldaten verfeinert. Sr3Cl2CBN kristallisiert isotyp zu Ca3Cl2CBN in der orthorhombischen Raumgruppe Pnma (Nr. 62) mit a = 1448,4(2) pm, b = 405,46(5) pm, c = 1170,1(1) pm. Die Gitterkonstanten von Ca3Br2CBN und Sr3Cl2CBN wurden durch orthorhombische Indizierung der Pulverdiagramme bestimmt (Ca3Br2CBN: a = 1444,3(2) pm, b = 390,64(6) pm, c = 1139,2(2) pm; Sr3Cl2CBN: a = 1444,0(4) pm, b = 405,27(8) pm, c = 1167,8(2) pm). Es gelang nicht, Barium-homologe darzustellen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 2083-2088 
    ISSN: 0044-2313
    Keywords: Tl3[Nb6SBr17] ; Cs3[Nb6SBr17] ; K3[Nb6SBr17] ; synthesis ; crystal structure ; electronic structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trigonal-prismatic Nb6-Units in Compounds of the Type A3[Nb6SBr17] (A = Tl, K, Cs)The new compounds A3[Nb6SBr17] (A = Tl, K, Cs) were synthesized and their lattice parameters were calculated from indexed X-ray powder patterns. An intensity measurement based on a single-crystal of Tl3[Nb6SBr17] was performed with an automatic four-circle diffractometer (a = 1704.9(1) pm, b = 1862.8(3) pm, c = 932.51(7) pm; β = 90.747(7)°, Vm = 445.9(3) cm3/mol; C2/c, Z = 4). The structure refinement confirmed consistency with the Rb3[Nb6SBr17] structure, found previously. The comparison of both structures yielded no significant differences concerning the distances within the sulfur-centered Nb6S cluster core.Extended Hückel calculations revealed a maximum of the niobium-niobium overlap populations for (the actual present number of) 14 electrons occupying metal-metal bonding states.
    Notes: Die neuen Verbindungen A3[Nb6SBr17] mit A = Tl, K, Cs wurden dargestellt und ihre Gitterkonstanten aus Röntgen-Pulverdiagrammen ermittelt. An einem Einkristall von Tl3[Nb6SBr17] wurde eine Intensitätsmessung mit einem automatischen Vierkreisdiffraktometer vorgenommen (a = 1704,9(1)pm, b = 1862,8(3)pm, c = 932,51(7)pm; β = 90,747(7)°, Vm = 445,9(3) cm3/mol; C2/c, Z = 4). Die Strukturverfeinerung bestätigte die Übereinstimmung mit der vor kurzem verfeinerten Struktur von Rb3[Nb6SBr17]. Ein Vergleich beider Verbindungen zeigt keine signifikanten Unterschiede der interatomaren Abstände für die schwefelzentrierten Nb6S-Cluster.Extended-Hückel-Berechnungen ergaben ein relatives Maximum der Niob-Niob-Überlappungspopulationen für (die tatsächlich vorliegende Anzahl von) 14 Elektronen in den Metall-Metall-bindenden Zuständen des Clusters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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