Preparation and Structures of [W(CH3)6], [Re(CH3)6], [Nb(CH3)6], and [Ta(CH3)6]

Varying degrees of distortion from trigonal-prismatic symmetry are observed in the crystal structure determinations of the title compounds. A strongly distorted trigonal-prismatic C3v symmetry was found for [W(CH3)6], a regular trigonal-prismatic symmetry for [Re(CH3)6], and both [Ta(CH3)6]− and [Nb(CH3)6]− show a slight distortion from an ideal trigonal prism. The reasons for these different distortions are discussed. The top view of [W(CH3)6] is shown on the right.