中国科学院地球化学研究所机构知识库

The compression behavior of a synthetic Ca4La6(SiO4)(6)(OH)(2) has been investigated to about 9.33 GPa at 300 K using in situ angle-dispersive X-ray diffraction and a diamond anvil cell. No phase transition has been observed within the pressure range investigated. The values of zero-pressure volume V (0), K (0), and refined with a third-order Birch-Murnaghan equation of state are V (0) = 579.2 +/- A 0.1 (3), K (0) = 89 +/- A 2 GPa, and . If is fixed at 4, K (0) is obtained as 110 +/- A 2 GPa. Analysis of axial compressible modulus shows that the a-axis (K (a0) = 79 +/- A 2 GPa) is more compressible than the c-axis (K (c0) = 121 +/- A 7 GPa). A comparison between the high-pressure elastic response of Ca4La6(SiO4)(6)(OH)(2) and the iso-structural calcium apatites is made. The possible reasons of the different elastic behavior between Ca4La6(SiO4)(6)(OH)(2) and calcium apatites are discussed.