SEM, EDX and vibrational spectroscopic study of the carbonate mineral donnayite-(Y) NaCaSr3Y(CO3)6·3H2O

The mineral donnayite-(Y) has been studied by scanning electron microscopy with chemical analysis using EDX and vibrational spectroscopy. Multiple carbonate stretching modes are observed and support the concept of non-equivalent carbonate units in the donnayite-(Y) structure. Intense sharp bands at 464, 479 and 508 cm−1 are assigned to YO stretching modes. Raman bands at 765 and 775 cm−1 are assigned to the CO32−ν4 bending modes and Raman bands at 589, 611, 674 and 689 cm−1 are assigned to the CO32−ν2 bending modes. Multiple Raman and infrared bands in the OH stretching region are observed, proving the existence of water in different molecular environments in the structure of donnayite-(Y).