Tungstotellurates of the imidazolium and 4-methylimidazolium cations

Tungstotellurates of the organic imidazolium and 4-methyl-imidazolium catio ns have been prepared and characterized by X-ray diffraction and i.r. spect roscopy. The [TeW6O24](6-) anion is formed by close packing of oxygen atoms with Te and W atoms in distorted octahedral voids. In both compounds the o rganic cations are involved in hydrogen bonds, to the [TeW6O24](6-) anion i n [H(2)imz](6)[TeW6O24] . 2(Himz) (1) and to Te(OH)(6) units in [4-H-2-meth yl-imz](6)[TeW6O24] . Te(OH)(6) (2). Solution studies of (1) and (2) by H-1 -, W-183- and Te-125-n.m.r. have been carried out. Thermogravimetric (t.g.) and calorimetric (d.s.c.) analyses were performed for both compounds.