Thermal expansion of fluorapatite-hydroxylapatite crystalline solutions

Fluorapatite has been synthesized through ion-exchange between NIST hydroxylapatite SRM 2910a and optical-grade fluorite. The latter end-member and additional intermediate F-OH apatite samples made through ion-exchange between the newly synthesized fluorapatite and the original hydroxylapatite have provided materials for an investigation of thermal expansion in the F-OH apatite system. Unit-cell volumes determined from X-ray powder diffraction data collected between 22 and 928 C have been utilized to compute the coefficients of thermal expansion at a pressure of 1 bar for seven apatite samples having various F:OH ratios, as well as for natural samples of fluorapatite and hydroxylapatite. Results show that the thermal expansion coefficient for volume averages 41.0 +/- 1.4 (1 sigma) x 10(-6) deg(-1) for all samples and is thus little affected by F :OH ratio. This study extends the thermodynamic characterization of this important mineral system, with potential applications for the geological, planetary, biological, medical, and materials-science communities.

Title	Thermal expansion of fluorapatite-hydroxylapatite crystalline solutions
Creator	Scott, B. T.
	Altomare, C. M.
	Morris, M. D.
	McCubbin, F. M.
	Leaman, A. R.
	Hovis, Guy L.
	Tomaino, G. P.
Publisher	American Mineralogist
Academic Department	Geology & Environmental Geosciences
Division	Natural Sciences
Organization	Lafayette College
Date Issued	2014
Date Available	2016-03-02T20:19:26Z
Type	Article
Language	English
Keyword	hydroxylapatite
	F-OH apatite
	fluorapatite
	thermal expansion
Bibliographic Citation	Hovis, G. L., et al. (2014) "Thermal expansion of fluorapatite-hydroxylapatite crystalline solutions." American Mineralogist 99 (11-12): 2171–2175.
Standard Identifier	Handle 10385/2086
Standard Identifier	DOI 10.2138/am-2014-4914
Permalink	http://hdl.handle.net/10385/2086
Rights Statement	In Copyright
Rights Holders	Mineralogical Society of America