A theoretical study of the enantiomer interconversion pathway relevant to racemization reactions of hexacoordinate transition-metal complexes is presented based on density functional calculations. The potential-energy surface for the trigonal twist pathway of the [Zr(SH)6]2− model compound has been explored. The optimum structure reproduces, to a very good approximation, the experimental geometry of the analogous compound in which the thiolato groups have C6H4-4-OMe substituents instead of H atoms. A barrier of about 19 kcal mol−1 is estimated for the racemization of [Zr(SH)6]2− and exploratory calculations for [Zr(SC6H4-4-OMe)6]2− indicate that a larger barrier should be expected. For the chiral homoleptic organometallic complexes [ZrMe6]2− and [RhMe6]3− no significant racemization barrier is expected.