Cation distributions within a cluster framework. Synthesis and structure of the carbon- and boron-centered zirconium cluster compounds KZr/sub 6/Cl/sub 15/C and CsKZr/sub 6/Cl/sub 15/B
The structures of the isotypic KZr/sub 6/Cl/sub 15/C and CsKZr/sub 6/Cl/sub 15/B have been established by single-crystal X-ray diffraction in space group Pmma, Z = 4 (R = 3.1, 3.9%, R/sub w/ = 3.2, 3.6%, respectively). These contain a matrix of Z-centered Zr/sub 6/Cl/sub 12/Z clusters linked together by trans-chlorine atoms to form separate linear and zigzag chains that are interconnected into a three-dimensional network by four additional bridging chlorides. This (Zr/sub 6/Cl/sub 12/Z)Cl/sub 6/2/ framework affords three types of chloride environments for the cations, a smaller one (a) of ten-coordination occupied by potassium or rubidium and a pair of larger sites (b) with lower multiplicity that are utilized by cesium etc. The two b-type metal sites exhibit (1) an elongated square-pyramidal environment which, for the matrix studied, leaves the cesium closer to four-coordinate and (2) a more distorted 6 + 2 position of 2/m symmetry. Some evident cation disorder especially in the b(2) site and a possible small distortion of the anion matrix are noted. Compounds of this type are made by the reaction of stoichiometric amounts of ZrCl/sub 4/ and Zr with C, B, or ZrNCl and the appropriate MCl in welded Ta containers at 850/sup 0/C. These reactions give, according to Guinier powder diffraction, > 95% yields of KZr/sub 6/Cl/sub 15/Z, Z = C or N, with occupancy of cation site a, the isotopic (Cs or Rb)Zr/sub 6/Cl/sub 15/C utilizing site b, and (CsK, Rb/sub 2/, or CsRB)Zr/sub 6/Cl/sub 15/B with a and b site occupancy. All but the nitride involve 14 cluster-bonding electrons, the most preferred state according to the MO scheme.
- Research Organization:
- Iowa State Univ., Ames
- OSTI ID:
- 6336002
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:16; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Comparative zirconium bromide cluster chemistry. A new structure in K{sub 4}Zr{sub 6}Br{sub 18}C
Zirconium bromide cluster chemistry. A new tunnel structure in A{sub 5}Zr{sub 6}Br{sub 15}Be (A = Rb, Cs)
Related Subjects
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
BORON COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CESIUM COMPOUNDS
CHEMICAL PREPARATION
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DATA
DIFFRACTION
EXPERIMENTAL DATA
HALIDES
HALOGEN COMPOUNDS
INFORMATION
LATTICE PARAMETERS
NUMERICAL DATA
POTASSIUM COMPOUNDS
SCATTERING
SPACE GROUPS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION
ZIRCONIUM CHLORIDES
ZIRCONIUM COMPOUNDS