Abstract: | The reaction of one equivalent of In with a molten flux of (Ph4P)2Se5 and P2Se5 (1 : 2), at 250 °C gave the (Ph4P)[In(P2Se6)] ( I ). Stoichiometric elemental synthesis at 750 °C produced the Cs5In(P2Se6)2 ( II ). The thin, yellow crystals of ( I ), and the irregular, dark orange crystals of ( II ), appear to be air- and water-stable. Compound ( I ) crystallizes in the monoclinic space group C2/c (no. 15) and at 23 °C: a = 23.127(7) Å, b = 6.564(1) Å, c = 19.083(3) Å, β = 97.42(2)°, V = 2873(1) Å3, Z = 4, final R/Rw = 4.4/5.2%. Compound ( II ) crystallizes in the tetragonal space group P42/m (no. 84) and at 23 °C: a = b = 13.886(1) Å, c = 7.597(2) Å, V = 1464.9(3) Å3, Z = 2, final R/Rw = 3.9/5.1%. Compound ( I ) contains infinite [In(P2Se6)]nn– with a structure related to that of K2FeP2Se6. Compound ( II ) contains the discrete [In(P2Se6)2]5– which can be viewed as a fragment of the [In(P2Se6)]nn– chain. |