The hexaosmium clusters in C,4kappa3C,5kappa3C,6kappa3C-hexaosmium-chl
oroform (1/1), [Os6(CO)18].CHCl3, have essentially the same internal g
eometry as in unsolvated Os6(CO)18 but participate in O...H and O...Cl
contacts with the chloroform solvate molecules.