Raman spectroscopic study of the tellurite mineral: Sonoraite Fe3+Te4+O3(OH) H2O

Tellurites may be subdivided according to formula and structure. Raman spectroscopy has been used to study sonoraite an example of a tellurite with hydroxyl and water units in the mineral structure. The free tellurite ion will have C3v symmetry and four modes, 2A1 and 2E. An intense Raman band at 779 cm-1 is assigned to the ν1 (TeO3)2- symmetric stretching mode. A band at 666 cm-1 with a shoulder at 638 cm-1 is assigned to the the ν3 (TeO3)2- antisymmetric stretching mode. Bands at 374 and 387 cm-1 and the two bands at 425 and 468 cm-1 are assigned to the (TeO3)2- ν2 (A1) bending mode and (TeO3)2- ν4 (E) bending modes. The sharp band at 3423 cm-1 assigned to the OH stretching vibration of the OH units is superimposed upon a broader spectral profile with Raman bands at 3000, 3223, 3350 and 3450 cm-1 are attributed to water stretching bands. The technique of Raman spectroscopy is excellent for the study of tellurite minerals.