RESEARCH ON TRINUCLEAR MOLYBDENUM CLUSTER COMPOUNDS——CRYSTAL AND MOLECULAR STRUCTURE OF Mo_3(μ_3-S)(μ_2-S_2)_3[S_2P(OEt)_2]_3Cl

The title crystal is straw-yellow in colour, belonging to the triclinic system. The space group is P with the following unit cell parameters:a=11.570(2), b=13.093(1), c=14.399(2), α=102.62(1), β=102.15(1), γ=111.87 (1)°, V=1870(1), Z=2, D_(calc)=1.960g·cm~(-3).The crystal structure was solved by the heavy atom method and refined by full-matrix least-squares to a final conventional R factor of 0.055. The results show that the crystal structure consists of neutral trinuclear Mo cluster molecules, in which three independent Mo atoms form an equilateral triangle with an average side length of 2.725(3), corresponding to a Me-Me single bond. On one side of the triangle one μ_3-S atom binds the three Mo atoms together to form a monoeapped trinuclear cluster. In addition, three S_2 radicals acting as μ_2 bridges are located between each two Mo atoms. Each Mo atom is also coordinated to two terminal S atoms of an S_2P(OEt)_2]~- radical so as to complete a distorted pentagonal bipyramid configuration.