Crystal and molecular structure of vanadium hexacarbonyl

Experimental V(CO) 6 is orthorhombic with a = 11.905 (7), b = 11.221 (20), c = 6.397 (4) A at 244-7 + 1.5 K, space group Pnma, Z = 4. The structure was refined to R --0.0329 for 990 unique reflexions. Mean V C and C O distances are 2.001 (2) and 1.128 (2) A respectively before librational correction and 2.008 and 1.139 A after. The molecular structure is very close to regular octahedral although there is a marginally significant tetragonal distortion with uncorrected bond lengths: V C (axial) 1.993 (2), (equatorial) 2.005 (2), C O (axial) 1. 136 (3), (equatorial) 1.123 (2) A. This represents a lower limit on a possible static Jahn-Teller distortion since a dynamic distortion is also possible: ,however, a vibrational analysis shows that dynamic effects, if present, are also small.