SYNTHESIS AND CRYSTAL-STRUCTURE OF SODIUM TETRAOXO NITRIDO TUNGSTATE(VI), NA5WO4N

Colourless crystals of Na5WO4N are obtained besides Na4WO2N2 [1] by th e reaction of WO3 with NaNH2 (15:1) at 350-degrees-C less-than-or-equa l-to T less-than-or-equal-to 750-degrees-C in autoclaves to prevent ea rly decomposition of sodium amide. X-ray single crystal investigations are characterized by the following data: Na5WO4N: Cmc2, (No. 36), Z = 4 a = 9.873(2) angstrom, b = 5.769(l) angstrom, c = 10.648(2) angstro m Z(F2) greater-than-or-equal-to 3sigma(F(o)2) = 2182, Z(Var.) = 55, R /R(w) = 0.029/0.039 The structure contains the tetragonal pyramidal io n WO4N5- with nitrogen at the apex connected via Na+ ions irregularly coordinated by one nitrogen and four oxygen atoms of different anions.