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  • 1
    Electronic Resource
    Electronic Resource
    Reactions of Hexanuclear Niobium and Tantalum Halide Clusters with Mercury(II) Halides. I. Synthesis and structures of the semiconducting compounds [M6Br12(H2O)6][HgBr4] · 12H2O, M=Nb, Ta (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1247-1254 
    Details
    ISSN: 0044-2313
    Keywords: Cluster compounds ; crystal structures ; magnetic properties ; transport properties ; semiconducting properties ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen von Hexanuclearen Niob- und Tantal-Halogenid-Clustern mit Quecksilber(II)-Halogeniden. I. Synthese und Struktur der halbleitenden Verbindungen [M6Br12(H2O)6][HgBr4] · 12H2O, M=Nb, TaDie Darstellung der neuen Clusterverbindungen [M6Br12(H2O)6][HgBr2X2] · 12H2O (M=Nb, Ta; X=Cl, Br, I) wird beschrieben. Für [Nb6Br12(H2O)6][HgBr4] · 12H2O 1 und [Ta6Br12(H2O)6][HgBr4] · 12H2O 2 wurden die Strukturen röntgenographisch aus Einkristallen bestimmt: 1: kubisch, Raumgruppe Fd3m, a = 21.0072(6) Å, Z = 8, R = 0.051 (Rw = 0.066); 2: kubisch, Raumgruppe Fd3m, a = 20.9698(1) Å, Z = 8, R = 0.038 (Rw = 0.050). 1 und 2 enthalten ein oktaedrisches [M6Br12(H2O)6]2+-Cluster-Kation und ein tetraedrisches [HgBr4]2--Anion. Die M—M-Abstände betragen 2.949(1) Å für 1 und 2.9000(8) Å für 2 und die Hg—Br-Abstände 2.614(2) Å in 1 und 2.622(2) Å in 2. Die Kristallstrukturen der isotypen Clusterverbindungen 1 und 2 können mit einem dreidimensionalen Netz von H-Brücken beschrieben werden; die Kristallwassermoleküle sind Donatoren von Wasserstoffatomen zu den Bromatomen der Cluster-Kationen und zu [HgBr4]2--Anionen. Die koordinierten Wassermoleküle bilden Wasserstoffbrücken zu den Kristall-wassermolekülen. [Nb6Br12(H2O)6][HgBr4] · 12H2O ist diamagnetisch und halbleitend mit der Aktivierungsenergie, Ea = 0.20 eV.
    Notes: A method for the preparation of new solvated clusters of the composition [M6Br12(H2O)6][HgBr2X2] · 12H2O (M=Nb, Ta; X=Cl, Br, I) is given. The cubic crystals of [Nb6Br12(H2O)6][HgBr4] · 12H2O 1 and [Ta6Br12(H2O)6][HgBr4] · 12H2O 2 were characterized by the X-ray structure analysis: 1: cubic, space group Fd3m, a = 21.0072(6) Å, Z = 8, R = 0.051 (Rw = 0.066); 2: cubic, space group Fd3m, a = 20.9698(1) Å, Z = 8, R = 0.038 (Rw = 0.050). 1 and 2 contain octahedral cluster cation [M6Br12(H2O)6]2+ and tetrahedrally arranged [HgBr4]2- anion. The M—M bond distances are 2.949(1) Å for 1 and 2.9000(8) Å for 2. The Hg—Br bond distances in [HgBr4]2- anion are 2.614(2) Å in 1 and 2.622(2) Å in 2. The crystal packing patterns of the isostructural clusters 1 and 2 involve the three-dimensional hydrogen bond network; the crystalline water molecules act as donors of hydrogen to the bromine atoms of the cluster and [HgBr4]2- units, whereas the coordinated water molecules form hydrogen bonds to the crystalline water molecules. [Nb6Br12(H2O)6][HgBr4] · 12H2O is diamagnetic and semiconducting with the activation energy, Ea = 0.20 eV.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230811
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  • 2
    Electronic Resource
    Electronic Resource
    Crystal Structures of trans-[Ta6Cl12(OH)4(H2O)2] · 10 H2O and (NMe4)2[Ta6Cl12(OH)6] · 21 H2O (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 59-64 
    Details
    ISSN: 0044-2313
    Keywords: Hexanuclear tantalum chloro cluster ; tantalum cluster hydroxide ; mixed coordinated clusters ; intercluster bridges ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Kristallstrukturen von trans-[Ta6Cl12(OH)4(H2O)2] · 10 H2O und (NMe4)2[Ta6Cl12(OH)6] · 21 H2ODie Verbindungen trans-[Ta6Cl12(OH)4(H20)2] · 10H2O 1, (NMe4)2[Ta6Cl12(OH)6] · 21H2O 2 und Na2[Ta6Cll2(OH)6] · 16H2O 3 enthalten oktaedrische Tantalchlorocluster und können aus alkalischer Lösung (Methanol/Wasser) erhalten werden. Die Strukturen von 1 und 2 werden beschrieben. Kristallographische Daten s. Abstract.Die Verbindung 1 enthält neutrale, gemischt-koordinierte trans-[Ta6Cl12(OH)4(H2O)2]- Einheiten mit Ta—OH- und Ta—OH2Abständen von 210,4(5) und 214,5(5) pm. Ein koordiniertes Wassermolekül eines Clusters und eine OH Gruppe eines benachbarten Clusters bilden H3O2--Brücken mit einem O … H—O-Abstand von 253,7(7) pm zwischen den beiden Clustern aus. Die zwölf Ta—Cl-Abstände liegen zwischen 244,1(2) und 245,2(2) pm. Die Struktur von 2 ist aus [Ta6Cl12(OH)6]2--Anionen, NMe4+-Kationen und über H-Brücken gebundenen Wassermolekülen aufgebaut.
    Notes: The compounds trans-[Ta6Cl12(OH)4 (H2O)2] · 10 H2O 1, (NMe4)2[Ta6Cl12(OH)6] · 21 H2O 2 and Na2[Ta6Cl12(OH)6] · 16 H2O 3 containing octahedral tantalum chloro clusters were isolated from alkaline methanol/water solutions of [Ta6Cl12]4+. Crystal structures were solved for 1 and 2. Crystal data: 1, monoclinic, space group P21/c (No. 14), a = 938.5(2) pm, b = 1220.3(2) pm, c = 1391.7(4) pm, β = 103.87(2)°, V = 1547.5(6) × 106 pm3, Z = 2; 2, rhombohedral, space group R3 (No. 148), a = 1201.4(2) pm, c = 3110.8(6) pm, V = 3888.5(12) × 106 pm3, Z = 3; 3, cubic F lattice, a = 1451(2) pm, V = 3055(13) × 106 pm3, Z = 4.The cluster in 1 contains the neutral, mixed-coordinated trans-[Ta6Cl12(OH)4 (H2O)2] cluster with Ta—OH and Ta—OH2 distances of 210.4(5) pm and 214.5(5) pm, respectively. One coordinated H2O molecule from one cluster and a coordinated OH- group from a neighbouring cluster form H3O2- intercluster bridges with the O … H—O distance 253.7(7) pm. Twelve Ta—Cl (bridging) distances range from 244.1(2) to 245.2(2) pm. The structure of 2 is built of [Ta6Cl12(OH)6]2- anions, NMe4+ cations and water molecules, the latter linked to the anions by hydrogen bonds.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976230110
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  • 3
    Electronic Resource
    Electronic Resource
    Classification of the Niobium and Tantalum Clusters [M6X12i]X2a · nH2O; M = Nb, Ta; Xi = Cl, Br; Xa = Cl, Br, I, OH, According to their X-ray Patterns (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 472 (1981), S. 200-204 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Klassifikation der Niob- und Tantal-Cluster [M6X12i]X2a · nH2O (M = Nb, Ta; Xi = Cl, Br; Xa = Cl, Br, I, OH) auf Grund ihrer RöntgendiagrammeRöntgendiagramme der Cluster-Verbindungen [M6X12i]X2a · nH2O (M = Nb, Ta; Xi = Cl, Br; Xa = Cl, Br, I, OH) (i = innen, a = außen) wurden gemessen und verglichen. Entsprechend können Clusterhydroxide [M6Br12](OH)2 · 8 H2O in die bereits bekannte Strukturgruppe B eingeteilt werden. Analoge Chloroclusterhydroxide bilden die separate Strukturgruppe E.
    Notes: X-ray diffraction patterns for the cluster compounds [M6X12i]X2a · nH2O, M = Nb, Ta; Xi = Cl, Br; Xa = Cl, Br, I, OH (i  -  inside, a  -  outside) have been measured and compared, according to which cluster hydroxides [M6Br12](OH)2 · 8 H2O can be classified in the previously known structural group B. Analogous chloro-cluster hydroxides form a separate structural group E.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814720124
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  • 4
    Electronic Resource
    Electronic Resource
    Reactions of the early transition metal clusters with aliphatic alcohols. Part I. Preparation, properties, and structural classification of [M6Cl12](OH)2 · 6 H2O · 2 CH3OH (M = Nb, Ta) (1982)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 489 (1982), S. 235-239 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen von Übergangsmetallclustern mit aliphatischen Alkoholen. Teil I. Darstellung, Eigenschaften und strukturelle Klassifikation von [M6Cl12] (OH)2 · 6 H2O · 2 CH3OH (M = Nb, Ta)Die Darstellungsbedingungen kristallisierter Verbindungen des Typs [M6Cl12](OH)2 · 6 H2O · 2 CH3OH (M = Nb, Ta) werden beschrieben. Auf Grund von Röntgenaufnahmen konnten diese isomorphen Verbindungen keiner der fünf bisher bekannten Gruppen von Niob- oder Tantalclustern [M6X12]2+ zugeordnet werden. Die physikalischen und spektroskopischen Eigenschaften dieser Verbindungen werden mit denen der korrespondierenden 8-Hydrate [M6X12] (OH)2 · 8 H2O und anderer Nb- und Ta-Clustern verglichen.
    Notes: The conditions of preparation of the crystalline compounds of the type [M6Cl12] (OH)2 · 6 H2O · 2 CH3OH, M = Nb, Ta, have been described. According to the X-ray diffraction patterns, it is not possible to classify these isomorphous substances, in the five already known structural groups of [M6X12]2+ clusters of niobium and tantalum. Physical and spectral properties of these compounds are compared with the corresponding octahydrates [M6X12](OH)2 · 8 H2O and other clusters of niobium and tantalum.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19824890128
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