Five Eu2+-doped simple fluorides and 6 Eu2+-doped complex fluorides were synthesized by solid reactions. The strength of the crystal-field at the sites of Eu2+ ion, and the degree of covalence of Eu-F bond in these hosts are discussed. The f-f transition emission of Eu2+ ion was observed in the hosts which has lower coordination no. and strong crystal-field. The f-f transition emission of Eu2+ ion was observed for the 1st time in the simple fluoride AlF3.

Key words: FLUORIDE, EUROPIUM COMPOUNDS, CHEMICAL BONDS, TRANSITION, CRYSTAL FIELD THEORY, FLUOROSPECTROPHOTOMETRY