Rearrangement of the {Mo6S8}cluster fragment to {Mo4S4} and a New {Mo6S6} Cluster Nucleus: Crystal Structure of K6[Mo4S4(CN)12]·10H2O and (18-Crown-6K)8[Mo6S6(CN)16]·17.5H2O

Two new compounds containing molybdenum thiocyanide cluster anions, K₆[Mo₄S₄(CN)₁₂]·10H₂O (1) and (18-crown-6K)₈[Mo₆S₆(CN)₁₆]·17.5H₂O (2), were synthesized and investigated by X-ray structure analysis. Crystal data: a=11.8430(17), b=11.8430(17), c=35.170(7) , V=4932.8(14) ³, space group I4₁/a, Z=4, d_calc=1.563 g/cm³ for 1; a=28.7513(5), b=18.4190(3), c=20.7586(4) , =118.5982(7)°, V=9651.9(3) ³, space group C2/m, Z=4, d_calc =1.563 g/cm³ for 2. The [Mo₄S₄(CN)₁₂]^6- cluster anion in 1 has an ordinary structure typical of cubane transition metal complexes. In the structure of the [Mo₆S₆(CN)₁₆]^8- anion of 2, two crystallographically independent molybdenum atoms form a Mo₆ metallocluster, represented as two edge-sharing tetrahedra.