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Synthesis, Structure, and Thermal Properties of Soluble Hydrazinium Germanium(IV) and Tin(IV) Selenide Salts

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journal contribution
posted on 16.05.2005, 00:00 by David B. Mitzi
The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N2H5)4Ge2Se6 (1) [I41cd, a = 12.708(1) Å, c = 21.955(2) Å, Z = 8] and (N2H4)3(N2H5)4Sn2Se6 (2) [P1̄, a = 6.6475(6) Å, b = 9.5474(9) Å, c = 9.8830(10) Å, α = 94.110(2)°, β = 99.429(2)°, γ = 104.141(2)°, Z = 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M2Se64- (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N2H5)4Sn2S6, decomposes cleanly to microcrystalline SnS2 when heated to 200 °C in an inert atmosphere, higher temperatures (>300 °C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films.