SYNTHESIS AND REACTIONS OF [ET3NH]4[MO8O26] - X-RAY CRYSTAL-STRUCTUREOF [ET3NH]3[NAMO8O26]

[Et3NH]4[Mo8O26] (1) was prepared by reacting triethylamine with eithe r molybdenum trioxide dihydrate or with a solution of ammonium molybda te in aqueous HCl. An aqueous solution of complex 1 reacted with an ex cess of sodium chloride to give a mixture of [Et3NH]3[NaMo8O26] (2) an d [Et3NH]2[Mo6O19] (3). Complex 2 was also formed on reacting sodium m olybdate with triethylamine in aqueous HCl. In the reaction of 1 with potassium chloride the nature of the product obtained was critically d ependent upon reaction time. After a 5.5 h reflux period a mixture of [Et3NH]3[KMo8O26] (4) and 3 was obtained, whereas upon prolonged reflu x (24 h) only K4Mo8O26 . H2O (5) was precipitated. The X-ray crystal s tructure of 2 shows it to be polymeric, with each Na+ ion sandwiched b etween two beta[Mo8O26]4- ions. Four oxygen atoms on one face of each beta[Mo8O26]4- ion are coordinated to a Na+ ion, and four oxygens from the opposite face are bonded to the next Na+ ion in the polymer chain . This produces a zig-zag arrangement of Na+ ions throughout the molec ular structure. Spectral, conductivity and voltammetry data are given.