Rare-earth-metal iodide clusters centered by transition metals: Synthesis, structure, and bonding of R sub 7 I sub 12 M compounds (R = Sc, Y, Pr, Gd; M = Mn, Fe, Co, Ni)
- Iowa State Univ., Ames (USA)
The compounds R{sub 7}I{sub 12}M (M = Co, Ni for R = Sc; M = Fe, Co for R = Y; M = Mn, Fe, Co for R = Gd; M = Mn, Fe, Co, Ni for R = Pr) have been synthesized by reactions of RI{sub 3}, MI{sub 2}, and R metals at 750-950{degree}C in sealed Nb or Ta containers. These compounds all adopt the Sc(Sc{sub 6}Cl{sub 12}B) structure (space group R{bar 3}, Z = 3) with a transition metal at the cluster center (in place of boron). The seventh isolated R{sup 3+} ion can be substituted by Ca{sup 2+} in several of the Pr and Gd cases. The structural details of Sc{sub 7}I{sub 12}Co, Y{sub 7}I{sub 12}Fe, and (Ca{sub 0.65}Pr{sub 0.35})(Pr{sub 6}I{sub 12}Co) were determined by single-crystal x-ray diffraction methods (a = 14.800, 15.351, 15.777 {angstrom}; c = 10.202, 10.661, 10.925 {angstrom}; R = 3.3, 3.8, 3.4%; R{sub w} = 6.7, 3.3, 3.5%, respectively). The last of these presented twinning difficulties endemic to this structure type, but these were overcome satisfactorily by an approximate separation procedure. R-M distances in the clusters are short; Pr-Co = 2.770, Y-Fe = 2.621, and Sc-Co = 2.431 {angstrom}. While MO theory provides some useful guides to these compounds stability, the true breadth of the chemistry possible remains to be explored. 28 refs., 2 figs., 4 tabs.
- OSTI ID:
- 7108174
- Journal Information:
- Inorganic Chemistry; (USA), Vol. 26:12; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT COMPOUNDS
SYNTHESIS
GADOLINIUM COMPOUNDS
IODIDES
IRON COMPOUNDS
MAGNESIUM COMPOUNDS
NICKEL COMPOUNDS
PRASEODYMIUM COMPOUNDS
SCANDIUM COMPOUNDS
YTTRIUM COMPOUNDS
CRYSTAL STRUCTURE
EXPERIMENTAL DATA
MOLECULAR STRUCTURE
ALKALINE EARTH METAL COMPOUNDS
DATA
HALIDES
HALOGEN COMPOUNDS
INFORMATION
IODINE COMPOUNDS
NUMERICAL DATA
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties