The luminescence of Cs2NaSbCl6 AND Cs2NaSbBr6: a transition from a localized to a delocalized excited state

The luminescences of Cs2NaSbCl6 and Cs2NaSbBr6 are reported. For Cs2NaSbBr6 the luminescence properties are described in terms of a band model. For Cs2NaSbCl6 the luminescence is interpreted in terms of isolated Sb3+ centres, comparable with Cs2NaMCl6−Sb3+ (M = Sc, Y, La). The radius of the Sb3+ ion is larger in the chloro- than in the bromo-elpasolite.