Structural modification-induced valence change of the europium ion doped in barium octaborate

Valence states of the europium ion doped in barium octaborate, BaB8O13, wer e alternately changed between the trivalent and divalent ones by performing the crystallization or vitrification treatment for the host material in ai r at 973-1273 K, and such valence change characteristics were discussed on the basis of the mutual transformation between BO3 and BO4 units and their connection manners via bridged oxygens in the networks of crystalline and v itreous BaB8O13 forms, so that the redox mechanism proposed was applied to other metal borate host materials to predict and control the valence state of Eu ions. (C) 1999 The Electrochemical Society. S1099-0062(99)07-007-8. A ll rights reserved.