Thermodynamic investigation on beta- and gamma-Ca-3(PO4)(2) and the   phase equilibria

doi:10.1016/j.pepi.2013.07.009

CORC > 北京大学 > 地球与空间科学学院

	Thermodynamic investigation on beta- and gamma-Ca-3(PO4)(2) and the phase equilibria
	Zhai, Shuangmeng ; Akaogi, Masaki ; Kojitani, Hiroshi ; Xue, Weihong ; Ito, Eiji
刊名	physics of the earth and planetary interiors
	2014
关键词	Ca-3(PO4)(2) Tuite Whitlockite Thermodynamic property Phase boundary FERRITE-TYPE MGAL2O4 TRICALCIUM PHOSPHATE HIGH-TEMPERATURE HEAT-CAPACITY LATTICE-VIBRATIONS HIGH-PRESSURE RAMAN-SPECTROSCOPY DENSE POLYMORPH SHOCK VEINS METEORITE
DOI	10.1016/j.pepi.2013.07.009
英文摘要	gamma-Ca-3(PO4)(2), naturally known as tuite, is regarded as an important potential reservoir for rare earth elements and large ion lithophile elements. It is a high-pressure polymorph of beta-Ca-3(PO4)(2) whitlockite and a decomposed product of apatite under high-pressure and temperature. Drop-solution enthalpies of beta- and gamma-Ca-3(PO4)(2) were obtained as 298.59 +/- 3.02 and 278.74 +/- 2.98 kJ/mol, respectively, by the drop-solution calorimetry with 2PbO center dot B2O3 solvent at 978 K. Thus the enthalpy of transition from beta- to gamma-Ca-3(PO4)(2) at 298 K (Delta H-tr,298(o)) was 19.85 +/- 4.24 kJ/mol. The isobaric heat capacities of beta- and gamma-Ca-3(PO4)(2) were measured at temperature range of 300-770 K by differential scanning calorimetry, and compared with the results calculated from the Kieffer model. The equilibrium phase boundary between beta- and gamma-Ca-3(PO4)(2) was calculated using present measured data combined with other available thermochemical and thermoelastic data. The calculated boundary gave a phase transition boundary with a dP/dT slope of 4.7 +/- 0.2 MPa/K in the temperature range of 900-2000 K. Based on the phase relationship, the occurrences of tuite and whitlockite in meteorites are discussed. (C) 2013 Elsevier B.V. All rights reserved.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000337014100015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Geochemistry & Geophysics; SCI(E); EI; 4; ARTICLE; zhai@pku.edu.cn; ,SI; 144-149; 228
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/155503]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Zhai, Shuangmeng,Akaogi, Masaki,Kojitani, Hiroshi,et al. Thermodynamic investigation on beta- and gamma-Ca-3(PO4)(2) and the phase equilibria[J]. physics of the earth and planetary interiors,2014.
APA	Zhai, Shuangmeng,Akaogi, Masaki,Kojitani, Hiroshi,Xue, Weihong,&Ito, Eiji.(2014).Thermodynamic investigation on beta- and gamma-Ca-3(PO4)(2) and the phase equilibria.physics of the earth and planetary interiors.
MLA	Zhai, Shuangmeng,et al."Thermodynamic investigation on beta- and gamma-Ca-3(PO4)(2) and the phase equilibria".physics of the earth and planetary interiors (2014).