A high-yield procedure is described for the preparation, from [M(CO)(3
)Cl-2](2) (M = Ru, Os) and aqueous NaOH, of the new water-soluble and
air-stable species [Ru(CO)(2)Cl(OH)](n), [Ru(CO)(2)(OH)(2)](n), [Os(CO
)(3)Cl(OH)](2), and [Os(CO)(3)(OH)(2)](x) (x = 2 or n).