XAFS INVESTIGATION OF CU(I) LOCAL ENVIRONMENT IN 2 TYPES OF GLASSES OF BASE COMPOSITION LAMGB5O10 AND LILAP4O12

X-ray absorption spectroscopy (XAFS) has been used to characterise the local environment around Cu+ ions in two types of glasses of base com position LaMgB5O10 and LiLaP4O12. In both glasses, Cu+ is surrounded b y two oxygens respectively at 1.87 and 1.86 Angstrom For the first tim e in glasses, the formation of Cu+-Cu+ pairs (d(Cu-Cu) = 2.35 Angstrom ) is clearly evidenced in the phosphate. These results will be discuss ed with respect to the crystal chemistry of Cu(I) in copper oxides and the specific luminescent properties of an isolated Cu+ centre or Cu+- Cu+ pairs. (C) 1997 Elsevier Science S.A.