A Raman spectroscopic study of the antimonite mineral peretaite Ca(SbO) 4(OH) 2(SO 4) 2·2H 2O

Abstract

Raman spectra of mineral peretaite Ca(SbO) 4(OH) 2(SO 4) 2·2H 2O were studied, and related to the structure of the mineral. Raman bands observed at 978 and 980 cm −1 and a series of overlapping bands observed at 1060, 1092, 1115, 1142 and 1152 cm −1 are assigned to the SO 4 2− ν 1 symmetric and ν 3 antisymmetric stretching modes. Raman bands at 589 and 595 cm −1 are attributed to the SbO symmetric stretching vibrations. The low intensity Raman bands at 650 and 710 cm −1 may be attributed to SbO antisymmetric stretching modes. Raman bands at 610 cm −1 and at 417, 434 and 482 cm −1 are assigned to the SO 4 2− ν 4 and ν 2 bending modes, respectively. Raman bands at 337 and 373 cm −1 are assigned to O–Sb–O bending modes. Multiple Raman bands for both SO 4 2− and SbO stretching vibrations support the concept of the non-equivalence of these units in the peretaite structure.