Abstract: | Raman spectroscopy measurements of polycrystalline Na2MoO4·2H2O (NMHO) and Na2MoO4 (NM) under hydrostatic pressure (from 0 to 10 GPa) were performed. This study allowed us to monitor the stretching and bending vibrations of MoO4 ions as well as the translational modes as a function of pressure. The pressure dependence of the wavenumbers of the modes indicates that the Na2MoO4·2H2O undergoes two phase transitions at about ∼3 and ∼4 GPa. When releasing pressure, we have observed that the original spectrum is recovered, thereby pointing to a reversible process. The Na2MoO4 (NM) starting phase was found to be stable up to 10 GPa. The pressure‐dependent Raman data for NM did not reveal any structural modification. The influence of the pressure‐transmitting medium on the phase transitions is also discussed. Copyright © 2009 John Wiley & Sons, Ltd. |