Thermal Treatment of Moolooite: A High Resolution Thermogravimetric and Hot Stage Raman Spectroscopic Study

Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates. These oxalates form as a film like deposit on rocks and other host matrices. Moolooite as the natural copper (II) oxalate mineral is a classic example. High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition takes place at 260 degrees Celsius. Evolved gas mass spectrometry shows the gas lost at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper (II)oxalate as compared to the synthetic compound which is the dihydrate. The high resolution thermogravimetry was complimented with hot stage Raman spectroscopy. The temperature at which no intensity remains in the bands assigned to the oxalate vibrations is the upper limit of the stability of the moolooite.