Depending on the proticity of the solvent, two different salts may be crystallized from the combination of solutions of guanidinium chloride, C(NH2)3Cl, and the acidic hydrate of molybdenum dichloride, [(Mo6Cl8)Cl6](H20 O9). From aprotic solvents such as dimethyl sulfoxide (DMSO) or formamide (FA), compound I, [(Mo6Cl8) Cl6]Cl6(C(NH2)3)8, crystallizes, while from protic solvents such as ethanol or water, compound II, [(Mo6Cl8)Cl6]Cl3 (C(NH2)3)5, crystallises. In both compounds, the basic motif of the two parent structures, the octahedral [(Mo6Cl8)Cl6]2- cluster and the planar, triangular, C(NH2)3Cl3 entity are fairly well preserved. The assembly of the blocks, however, differs distinctly, and while both compounds are rather porous, compound I (s.g. Fm3̄m, No. 225) has a volume of 27 Å3/ non-hydrogen atom, compound II (s.g. C2/c, No. 15) is somewhat denser, with a volume of 24 Å3/non-hydrogen atom
