Image and spectra of single crystal raman spectroscopy of cerussite

The carbonates are a group of over 60 naturally occurring minerals containing the essential structural building block (CO3)2−. Most of these minerals are relatively rare and are often associated with other building blocks, such as hydroxyl, halogen, sulfate, silicate, phosphate, etc. The common simple rock-forming carbonates can be divided in three main groups:(1) the calcite group, (2) the dolomite group, and (3) the aragonite group. Cerussite is a member of the aragonite group, which contains the minerals aragonite (CaCO3), cerussite (PbCO3), strontianite (SrCO3), and witherite (BaCO3). This study examines the aragonite minerals to find the possible explanation of low intensity bands in cerussite in relation to the other aragonite minerals.

The cerussite sample was collected at Rum Jungle (Brown ’s Prospect), Northern Territory, Australia. A single crystal approximately 2 mm long was used for oriented single-crystal Raman microspectroscopy at room temperature. The cerussite sample was checked for phase impurities by X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray analysis before Raman microscopic analysis of the selected crystal.

Figure 1 shows (a) SEM image of cerussite. (B) SEM image of synthetic cerussite.  Figure 2 is the Raman spectra of (a) cerussite at 298 K, (B) 77 K, (c) witherite at 298 K, (d) 77 K, (e) strontianite at 298 K, (f) 77 K, (g) witherite at 298 K, and (h) 77 K. Figure 3 shows Raman spectra in the ν1 region for orientated cerussite crystals.  Figure 4 is the infrared spectrum of cerussite. Figure 5 is Raman spectra in the ν3 region for orientated cerussite crystals.  Figure 6 is Raman spectra in the ν4 region for orientated cerussite crystals. Figure 7 is Raman spectra in the lattice region for orientated cerussite crystals.