REACTION OF TRISELENIUM HEPTOXIDE WITH PYRIDINE - NOVEL DA-COMPLEX 4PY-CENTER-DOT-SE2O5

Se3O7 reacts with an excess of pyridine (Py) and forms the donor-accep tor (DA) complexes Py . SeO2, and 4Py . Se-2,O-5 The latter compound w as characterised by elemental analysis, Raman spectroscopy, thermal an alysis and X-ray crystallography: orthorhombic system, space group Pbc a with a =17.133(5) Angstrom, b = 11.585(6)Angstrom c = 22.461(6) Angs trom calculated density 1.652 g cm(-3), Z = 8, reflections collected, 2569, final R value 0.0442. This is the first compound in which tetrav alent selenium atom is co-ordinated by three nitrogen atoms.