SYNTHESIS OF THE ONE-DIMENSIONAL COMPOUND (PH4P)[IN(P2SE6)] IN A PH4P-CONTAINING SELENOPHOSPHATE FLUX, AND STRUCTURE OF [IN(P2SE6)(2)](5-) - A DISCRETE MOLECULAR FRAGMENT OF THE [IN(P2SE6)](N)(N-) CHAIN()

The reaction of one equivalent of In with a molten flux of (Ph4P)(2)Se -5 and P2Se5 (1:2), at 250 degrees C gave the (Ph4P)[In(P2Se6)] (I). S toichiometric elemental synthesis at 750 degrees C produced the Cs5In( P2Se6)(2) (II). The thin, yellow crystals of (I), and the irregular, d ark orange crystals of (II), appear to be air-and water-stable. Compou nd (I) crystallizes in the monoclinic space group C2/c (no. 15) and at 23 degrees C: a = 23.127(7) Angstrom, b = 6.564(1) Angstrom, c = 19.0 83(3) Angstrom, beta = 97.42(2)degrees, V = 2873(1) Angstrom(3), Z = 4 , final R/R-w = 4.4/5.2%. Compound (II) crystallizes in the tetragonal space group P4(2)/m (no. 84) and at 23 degrees C: a = b = 13.886(1) A ngstrom, c = 7.597(2) Angstrom, V = 1464.9(3) Angstrom(3), Z = 2, fina l R/R-w = 3.9/5.1%. Compound (I) contains infinite [In(P2Se6)](n)(n-) 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 t he [In(P2Se6)](n)(n-) chain.