The cations of an ordered omphacite from the Tauern window were gradually disordered in piston cylinder experiments at temperatures between 850 and 1150 °C. The samples were examined by X-ray powder diffraction and then investigated using low-temperature calorimetry and IR spectroscopy. The low-temperature heat capacity data were used to obtain the vibrational entropies, and the line broadening of the IR spectra served as a tool to investigate the disordering enthalpy. These data were then used to calculate the configurational entropy as a function of temperature. The vibrational entropy does not change during the cation ordering phase transition from space group C2/c to P2/n at 865 °C but increases with a further temperature increase due to the reduction of short-range order.

在 850 至 1150 °C 温度下的活塞缸实验中，来自 Tauern 窗的有序绿辉石的阳离子逐渐无序。通过 X 射线粉末衍射检查样品，然后使用低温量热法和红外光谱进行研究。低温热容数据用于获得振动熵，红外光谱的线展宽作为研究无序焓的工具。然后使用这些数据来计算作为温度函数的构型熵。在 865 °C 下，在从空间群C2/c到P2/n 的阳离子有序相变过程中，振动熵没有变化，但由于短程有序度的减少，振动熵随着温度的进一步升高而增加。