Variable-Temperature and High-Pressure Micro-Raman Spectra of Inorganic Artists' Pigments: Crystalline Wulfenite , Lead(II) Molybdate(VI), PbMoO 4.

Variable-temperature (−150°C to 600°C) and high-pressure (up to ∼5 GPa) micro-Raman spectra have been obtained for the mineralwulfenite[lead(II) molybdate(VI), PbMoO4], a main constituent of the artists' pigment,orange molybdate. The spectra were quite similar in both the temperature and the pressure studies, except for broadening and shifting of some peaks. No phase changes were detected, although there is possibly some amorphization beginning at ∼600°C. The photoacoustic IR spectrum in the 1950–450 cm−1region is reported for characterization purposes. The long-term stability of PbMoO4with respect to extreme changes in both temperature and pressure illustrates the importance oforange molybdatein artwork and protective coatings. [ABSTRACT FROM PUBLISHER]