The present invention provides thioaluminate phosphor compounds BaAl.sub.2S.sub.4 and BaAl.sub.4S.sub.7 with novel crystal structures that have higher luminosity and improved color coordinates. The invention is also directed to rare earth element activated barium thioaluminate phosphor films comprising a phosphor compound having a novel crystal lattice structure that increases the electroluminescent light emission from the film. The phosphor films are for use in electroluminescent displays and in particular, thick film dielectric electroluminescent displays.