Solvothermal synthesis, crystal structure, and thermoanalytical investigations of the new layered thioantimonate(III) [Fe(C4H13N3)(2)]Sb6S10 center dot 0.5 H2O

The novel thioantimonate(III) [Fe(C4H13N3)(2)]Sb6S10.0.5 H2O was synthesise d under mild hydrothermal conditions by allowing elemental Fe, Sb, and S to react in a 50% diethylenetriamine (dien) solution. The compound crystallis es in the monoclinic space group C2/c with a = 33.789(3), b 8.5697(4), c = 24.620(2) Angstrom, beta = 118.411(8)degrees and V= 6270.3(7) Angstrom (3). In the crystal structure, five SbS3 trigonal pyramids and one SbS4 unit ar e interconnected by sharing common S atoms, forming Sb2S2, Sb4S4, and Sb5S5 heterocycles. The layered [Sb6S10](2-) anion is formed by condensation of the rings in the order Sb4S4-Sb5S5-Sb2S2-Sb5S5-Sb4S4. The interconnection o f the different Sb,S, heterocycles leads to the formation of a large Sb16S1 6 ring. The special geometries of the SbSx units and their interconnection results in a new and unprecedented architecture of the four-atoms thick thi oantimonate layer. The calculated bond valence sums (BVS) for the Sb atoms range from 3.07 to 3.16 v.u., indicating that the Sb atoms are formally tri valent. The [Fe(dien)(2)](2+) cations and the water molecule are located be tween neighbouring layers. The thermal behaviour of the compound was invest igated using DTA-TG measurements. Upon heating decomposition starts at abou t 200 degreesC, which is accompanied by the removal of the organic ligands and the incorporated water molecules. In the X-ray powder pattern of the de composition product, the three compounds Sb2S3, FeSb2S4, and FeS could be i dentified.