TUNGSTEN PAIR FORMATION IN TUNGSTEN OXYBROMIDE CHEMISTRY - THE CRYSTAL-STRUCTURE OF THE ONE-DIMENSIONAL AG0.37WOBR3

The oxytribromide Ag0.37WOBr3 crystallizes in the triclinic system: a = 3.766(3), b = 7.101(7), c = 10.49(1) Angstrom, alpha = 101.80(5)degr ees beta = 100.25(5)degrees, gamma = 105.34(5)degrees with the space g roup P (1) over bar. The crystal structure determined from single crys tal X-ray diffraction data is based on W2Br6 units, with short W-W dis tances, joined by W-O-W bonds to form [W2Br6O4/2](1)(infinity) infinit e chains developing along the a direction. Along the c direction, the cohesion between the chains is achieved by silver atoms which exhibit statistical distribution; along the b direction exist only van der Waa ls Br-Br contacts between adjacent chains. These weak Linkages between the chains in two directions of the space give a strong one-dimension al character to this new tungsten oxybromide. (C) 1998 Elsevier Scienc e Ltd.