Crystal Structure of (NH4)2[Mo3S(S2)6] Containing the Novel Isolated Cluster [MO3S13]2-

Abstract

The novel tri-nuclear metal-sulfur cluster [Mo₃S(S₂)₆]^2- can be obtained as its ammonium salt by the reaction of a Mo^iv containing aqueous solutions with polysulfide. Its crystal and molecular structure has been determined by a single crystal X-ray study. The crystals are monoclinic (space group Cm, with a = 11.577(6) Å, b = 16.448(7) Å, c = 5.716(2) Å, β = 117.30(3)°, V = 967.2 ų , Z = 2, d_exptl. = 2.54(2) g/cm³ , d_cal = 2.54 g/cm³). The structure consists of isolated [Mo₃S(S₂)₆]^2- units, with three Mo atoms at the vertices of a triangle. There are bridging as well as terminal S₂ ^2--ligands lying above and below the Mo₃-plane (bond distances: Mo-Mo = 2.722 Å, Mo-S(terminal) = 2.435, Mo-S(bridging) = 2.452, Mo₃-S = 2.353(4) Å and S-S = 2.04 Å (mean values)).