Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 8 June 1973:
Vol. 180. no. 4090, pp. 1055 - 1057
DOI: 10.1126/science.180.4090.1055
Prev | Table of Contents | Next

Articles

Monoclinic Hydroxyapatite

J. C. Elliott 1, P. E. Mackie 2, and R. A. Young 2

1 Georgia Institute of Technology, Atlanta, Georgia 30332, and London Hospital Medical College, London, England
2 Georgia Institute of Technology

The existence of a monoclinic phase of hydroxyapatite, Ca2(PO4)4OH, has been confirmed, by single-crystal structure analysis (weighted "reliability" factor = 3.9 percent on |F|2). The structure has space group P21/b, a = 9.4214(8) angstroms, b = 2a, c = 6.8814(7) angstroms, and ggr = 120°, and is analogous to that of chlorapatite. The distortions from the hexagonal structure with which the monoclinic structure is pseudosymmetric are similar to those in chlorapatite, including enlargement of that triangular array of oxygen atoms in which the chlorine ion or, in hydroxyapatite, the hydroxyl hydrogen ion is approximately centered. The hydroxyapatite specimen was prepared by the conversion of a single crystal of chlorapatite in steam at 1200°C, was mimetically twinned, and was approximately 37 percent monoclinic.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Clinohydroxylapatite: a new apatite-group mineral from northwestern Ontario (Canada), and new data on the extent of Na-S substitution in natural apatites.
A. R. CHAKHMOURADIAN and L. MEDICI (2006)
European Journal of Mineralogy 18, 105-112
   Abstract »    Full Text »    PDF »
Apatite - An Adaptive Framework Structure.
T. White, C. Ferraris, J. Kim, and S. Madhavi (2005)
Reviews in Mineralogy and Geochemistry 57, 307-401
   Full Text »    PDF »
Synthesis and NMR characterization (1H and 31P MAS) of the fluorine-free hydroxylapatite-britholite-(Y) series.
J. Imbach, F. Brunet, T. Charpentier, and J. Virlet (2002)
American Mineralogist 87, 947-957
   Abstract »    Full Text »    PDF »
The Crystal Structure of Apatite, Ca5(PO4)3(F,OH,Cl).
J. M. Hughes and J. Rakovan (2002)
Reviews in Mineralogy and Geochemistry 48, 1-12
   Full Text »    PDF »
Compositions of the Apatite-Group Minerals: Substitution Mechanisms and Controlling Factors.
Y. Pan and M. E. Fleet (2002)
Reviews in Mineralogy and Geochemistry 48, 13-49
   Full Text »    PDF »
Calcium Phosphate Biominerals.
J. C. Elliott (2002)
Reviews in Mineralogy and Geochemistry 48, 427-453
   Full Text »    PDF »
Electron paramagnetic resonance spectroscopic study of synthetic fluorapatite: Part I. Local structural environment and substitution mechanism of Gd3+ at the Ca2 site.
N. Chen, Y. Pan, and J. A. Weil (2002)
American Mineralogist 87, 37-46
   Abstract »    Full Text »    PDF »
Rare-earth elements in chlorapatite [Ca10(PO4)6Cl2]: Uptake, site preference, and degradation of monoclinic structure.
M. E. Fleet, X. Liu, and Y. Pan (2000)
American Mineralogist 85, 1437-1446
   Abstract »    Full Text »    PDF »
Implications of Atomic Substitutions and Other Structural Details in Apatites.
R.A. Young (1974)
Journal of Dental Research 53, 193-203
   PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)