The S-deficient compound {Mo3S4[S2P(OEt)2]3.H2O} was converted through the S addition reaction into S-rich compound {Mo3S7[S2P(OEt)2]3.I}(CH3C6H5) (I). I forms crystals in space group P1 with Z = 2, a 10.350(1), b 13.931(4), c = 16.396(3) ? a 103.69(2), b 86.62(1), g 11.99(2)? d.(calcd.) = 1.817 g cm-3, R = 0.042. The formulation of I is of the general type {Mo3(m3-Z)(m-S2)3[S2P(OEt)2]3.X} (Z = O, S; X = Cl, I). There exists an essentially equilateral triangle of Mo atoms with the Mo-Mo bond lengths being 2.721(1), 2.724(1), 2.725(1) ? resp. Moreover, each Mo atom is coordinated with 7 S atoms forming a distorted pentagonal bipyramid. On the top of 3 S atoms out of Mo plane there is an iodine atom connecting these S atoms with an average distance of 3.169 ? which is obviously shorter than the corresponding Van der Waals contact (~4.00 ?, showing a bonding interaction. The configuration of trinuclear Mo cluster is therefore stable.

Key words: CRYSTAL STRUCTURE DETERMINATION, X-RAY DIFFRACTION ANALYSIS, MOLYBDENUM COMPLEX, THIOPHOSPHATE, CLUSTER COMPOUND, PHOSPHORIC ACID ESTER, SULFIDE COMPLEX, CONFIGURATION