Original paper

Compressibility of a natural P4/nnc vesuvianite

Lai, Xiaojing; Zhu, Feng; Qin, Shan; Li, Yanchun; Liu, Jing; Wu, Xiang


In situ synchrotron-radiation powder X-ray diffraction was applied to a natural vesuvianite with P4/nnc structure, (Ca19.0Na0.259K0.012)?=19.271(Al9.089Fe3+ 1.376Ti0.341Mg2.156Fe2+ 0.216Mn0.008)?=13.186P0.098(Si17.977Al0.023)?=18O70.208(OH)7.792 by means of the diamond anvil cell technique up to 27.9 GPa at room temperature. The isothermal pressure?volume relationship of vesuvianite was well fitted by the third-order Birch-Murnaghan equation of state with V 0 = 2865.9(4) Å3, K 0 = 143(3) GPa and K 0' = 5.2(4). The compressibility of the structure is anisotropic with ? c = 2.76*10?3 GPa?1 > ? a = ? b = 2.14*10?3 GPa?1. Thermoelastic properties of vesuvianite were compared and analyzed with its structural analogues (grossular, hydrogrossular and epidote).


compressibilitydacequation of statevesuvianitex-ray diffraction