Synthesis and characterisation of a new hydrated bismuth (III) oxalate : Bi2_2(C2_2O4_4)3_3,6H2_2O

This study presents results on synthesis and crystal structure of a new hydrated bismuth(III) oxalate : Bi$_2$(C$_2$O$_{4}$)$_3$,6H$_2$O. This compound is obtained by precipitation from Bi(NO$_3$)$_3$ solution and oxalic acid. Its structure is determined by X-ray crystallographic analysis from a single crystal: it is monoclinic with a = 9.761(1)Å, b = 8.193(1)Å, c = 10.214(1)Å, $\beta$ = 99.66(1)$^{\circ}$, G.S. P2$_{1}$/n. Its chemical composition is confirmed by chemical analyses, FTIR and TG-DTA experiments

Vanadium and tellurium siloxane compounds as precursors of vanadium oxide and tellurium oxide silica materials

The twelve-membred vanadium containing siloxane ring [t-Bu2SiOV(O)ClO]3 (compound 1) and t-Bu2Si(OTeCl3)2 (compound 2) are efficient single-source precursors to vanadium and tellurium–silica materials. The ceramic conversions which occur pyrolytically at about 460 and 300°C for compounds 1 and 2, respectively lead to materials having the V2O5–SiO2 and TeO2–SiO2 compositions, respectively. Thermogravimetric and differential thermal analysis (TG–DTA), X-ray diffraction, 29Si, 51V and 125Te solid NMR as well as vibrational spectroscopy were used to characterise the materials. The molecular route to oxide materials, described here, could represent an alternative way to the sol–gel process

A new family of compounds with tetrahedral anions: PbnBiOn(XO4), X = V, P, As, n = 1, 2, 4. A comparison with lead oxysulfates PbnPbOn(SO4)

International audienceThe thermal behavior and crystallographic characteristics of nine compounds, Pb$_n$MO$_n$(XO$_4$) with M = Bi, Pb, X = V, P, As, S and n = 1, 2, 4, are reported. A previously reported γ phase for Pb$_2$BiO$_2$(VO$_4$) was shown to consist of a mixture of PbBiO(VO$_4$) and Pb$_4$BiO$_4$(VO$_4$) that resulted from a kinetically controlled decomposition of Pb$_2$BiO$_2$(VO$_4$) at elevated temperatures. The relationship between the α, β and δ transitions for Pb$_2$BiO$_2$(VO$_4$) was clarified. All of these phases contain the tetrahedral anion XO$_4$ that imparts thermal and structural similarities as well as specifications that can be ascribed to anion size differences

Vibrational spectra, phase transitions and force-fields in crystalline scandium hexafluorides

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