Synthesis, structure, and decomposition of (NH4)(2)[Mo6Cl14]center dot H2O

(NH4)(2)[MO6Cl14] . H2O (1) was prepared from reactions of MoCl2 in ethanol with aqueous NH4Cl solution. It crystallizes in the monoclinic space group I2/a (no. 15), Z= 4 with a = 912.3(1), b = 1491.2(2), c= 1724.8(2)pm, beta = 92.25(1)degrees; RI = 0.023 (based on F values) and wR2 = 0.059 (based on F-2 values), for all measured X-ray reflections. The structure of the clus ter anion can be given as [(Mo6Cl8i)Cl-6](2-) (i = inner, a = outer ligands ). Thermal stability studies show that 1 loses crystal water followed by th e loss of NH4Cl above 350 degrees C to yield MoCl2. The water-free compound (NH4)(2)[Mo6Cl14] (2) was synthesized by solid stat e reaction of MoCl2 and NH4Cl in a sealed quartz ampoule at 270 degrees C. No single-crystals could be obtained. Decompositions of 1 and 2 under nitro gen and argon exhibited the loss of NH4Cl at about 350 degrees C. Decomposi tion under NH3 resulted in the formation of MoN and Mo2N at 540 degrees C a nd 720 degrees C, respectively.