CRYSTAL-STRUCTURE ANALYSIS OF SILVER OXALATE, AG2C2O4, AND AN X-RAY-DIFFRACTION STUDY OF ITS SINGLE-CRYSTAL AT THE INITIAL-STAGE OF PHOTOLYSIS

The crystal structure of Ag2C2O4 was determined space group P2(1)/c, a = 3.4603(5) b = 6.1972(9), c = 9.548(2) Angstrom beta = 103.47(1)degr ees, V = 199.12(6) Angstrom(3), Z = 2, d(calc) = 5.066 g/cm(3) (Synter P2(1) automatic diffractometer, CuKa radiation, theta/2 theta scan mo de with a rate of 1.98-14.5 deg/min to 2 theta(max) = 115 degrees, 548 measured and 274 independent I-hkl, R(F) = 0.0259). The structure is channel type ionic, with single-layer packing of anions in the (100) p lane according to the hexagonal law. In the channels stretched along [ 100], there are silver diners with the Ag-Ag distance of 2.945 Angstro m. The C2O42- anion has ($) over bar 1 symmetry; the C-C bond lengths are 1.60(1) and C-O are 1.23(1) and 1.24(1) Angstrom. The observation and X-ray diffraction monitoring of the initial stage of photolysis al lowed us to conclude that it proceeds in a thin surface layer and has no effect on the crystal structure. The obtained results are discussed in the light of the literature data on the photolysis and thermolysis mechanisms of Ag2C2O4 The results of previous structural studies are analyzed.