SYNTHESIS AND CRYSTAL-STRUCTURE OF THE POTASSIUM IMIDO NITRIDO POLYTUNGSTATE(VI) K14W6N16NH

Dark-red, transparent crystals of potassium imido nitrido polytungstat e(VI) (K14W6N16NH) were obtained by the reaction of tungsten powder wi th an excess of KNH2 in autoclaves at 600-degrees-C for 6 days. The st ructure of this compound was determined from X-ray single-crystal data : space group, Pbcm; Z = 4, a = 9.738(3) angstrom, b = 12.527(4) angst rom, c = 24.04(1) angstrom; R/R(w) = 0.044/0.053, with N(F(o)2) greate r-than-or-equal-to 1784, N(var) = 134. K14W6N16NH contains comer-shari ng nitrogen tetrahedra around tungsten - [WN2N2/2] - which are linked together in six-membered rings in boat form. These rings are connected to each other in para-positions via imide groups - NH2 - to waved rop es which run along the b axis.