| Affiliation: | 1.Institute of Chemistry, Far Eastern Branch,Russian Academy of Sciences,Vladivostok,Russia;2.Nesmeyanov Institute of Organoelement Compounds,Russian Academy of Sciences,Moscow,Russia |
| Abstract: | (NH4)Sb4F13 crystals (I) are synthesized and their crystal structure (tetragonal crystal system: a = 9.6431(2) Å, c = 6.5503(2) Å, V = 609.11(3) Å3, Z = 2, d calc = 4.100 g/cm3, F(000) = 664, space group I4?) is determined. The main structural units of I are tetranuclear anionic [Sb4F13]? complexes and [NH4]+ cations. The anionic complexes are built of four SbF3 groups linked together by tetrahedral bridging fluorine atom. At room temperature the (NH4)Sb4F13 crystals are isostructural to previously studied МSb4F13 (М = K, Rb, Cs, and Tl). The study of 121,123Sb NQR spectra of compound I is performed in a range of 77-370 K, which shows that when the temperature decreases (<250 K) the substance exhibits piezoelectric properties, as do other compounds of this group, but with a violation of their isostructurality. |
