The high pressure and high-temperature behavior of MnCO3 was
investigated up to 55 GPa at ambient temperature and up to
573 K at ambient pressure by Raman spectroscopy, respectively.
Some new modes were detected at ∼16 and ∼32 GPa, which
were assigned to MnCO3-I below 16 GPa and to MnCO3-II above
32 GPa, and to a coexisting phase of them in between. The high
pressure vibration properties of all Raman modes, especially high
frequency modes, were systematically reported. The coexisting
phase of MnCO3-I and MnCO3-II had much easier compressibility
than the MnCO3-II phase. The thermal stability of MnCO3 was at
least to 573 K and its thermal expansion along the c axis was
easier than a and b axes.