Location of antimony in a halophosphate phosphor

The location of antimony in halophosphate phosphors has been probed by use of ${}_{}{}^{121}{}_{}{}^{}\mathrm{Sb}$ Mössbauer spectroscopy. It has been shown that the observed Mössbauer parameters can be understood if the antimony is at the phosphorous site, its ligands being three of the oxygen atoms of the phosphate group and a fluorine ion. The problem of maintenance of the halophosphate phosphors in relation to loss of the fluorine ions and to the ${\mathrm{Sb}}^{5+}$ concentration associated with an impurity phase has also been studied.