Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

Abstract

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K2SO4, and relative amounts of fluorine and SO4 groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb3Zr2F9SO4 · 2H2O, Cs2ZrF2(SO4)2 · 2H2O, Cs8Zr4F2(SO4)11 · 16H2O, and Cs2ZrF4SO4 offer the most efficient RL.