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), Journal Name: Inorganic Chemistry; (USA) Vol. 26:12; ISSN 0020-1669; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
COBALT COMPOUNDS
CRYSTAL STRUCTURE
DATA
EXPERIMENTAL DATA
GADOLINIUM COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
IODIDES
IODINE COMPOUNDS
IRON COMPOUNDS
MAGNESIUM COMPOUNDS
MOLECULAR STRUCTURE
NICKEL COMPOUNDS
NUMERICAL DATA
PRASEODYMIUM COMPOUNDS
RARE EARTH COMPOUNDS
SCANDIUM COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS