The thermal degradation of calcium oxalate monohydrate is studied by using diffuse reflectance Fourier transform infrared spectroscopy combined with quadrupole mass spectrometry (DRIFTS/MS). DRIFTS/MS results are correlated with thermogravimetric analyses to verify the thermal properties of samples studied. Infrared spectral evidence for CaC2O4·H2O dehydration and infrared spectra for three different CaC2O4 phases are given. In addition, the significance of a band at 1085 cm−1 assigned to CO22- which appears during the decomposition of CaC2O4 to CaCO3 is discussed.
Robert L. White and Jiu Ai, "Variable-Temperature Diffuse Reflectance Infrared Studies of Calcium Oxalate Monohydrate," Appl. Spectrosc. 46, 93-99 (1992)