Skip to main content
Log in

Structure and crystal chemistry of a dense polymorph of tricalcium phosphate Ca3 (PO4)2: A host to accommodate large lithophile elements in the earth's mantle

  • Published:
Physics and Chemistry of Minerals Aims and scope Submit manuscript

Abstract

A phase of Ca3 (PO4)2, synthesized at 12GPa and 2300° C, is structurally analyzed by the single crystal X-ray diffraction method. This Ca3(PO4)2 is found to be a dense polymorph of tricalcium phosphate isostructural with Ba3 (PO4)2 and named γ-Ca3 (PO4)2. In the structure of Ca3 (PO4)2, a phosphorus atom is tetrahedrally coordinated by oxygen atoms and calcium atoms occupy two types of large metal sites. The Ca(1) site has twelve oxygen neighbours with the mean bond length of 2.739 Å while the other Ca(2) site is coordinated by ten oxygen atoms with the mean Ca-O distance of 2.588Å. The structure is characterized by the translationally interconnected polyhedral sequence PO4-Ca(2)O10-Ca (1)O12-Ca (2)O10-PO4 in the direction of the c axis. This dense phase of Ca3(PO4)2 with two large metal sites may be an important host for very large lithophile elements in the deep upper mantle of the earth.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Beswick AE, Carmichael ISE (1978) Constraints on mantle source compositions imposed by phosphorus and the rare-earth elements. Contrib Mineral Petrol 67:317–330

    Google Scholar 

  • Calvo C, Gopal R (1975) The crystal structure of whitlockite from the Palermo Quarry. Am Mineral 60:120–133

    Google Scholar 

  • Coppens P, Hamilton WC (1970) Anisotropic extinction corrections in the Zachariasen approximation. Acta Crystallogr A26:71–83

    Google Scholar 

  • Dickens B, Schroeder LW, Brown WE (1974) Crystallographic studies of the role of Mg as a stabilizing impurity in β-Ca3 (PO4)2. I. The crystal structure of pure β-Ca3 (PO4)2. J Solid State Chem 10:232–248

    Google Scholar 

  • Dowty E (1977) Phosphate in Angra Dos Reis: structure and composition of the Ca3 (PO4)2 minerals. Earth Planet Sci Lett 35:347–351

    Google Scholar 

  • Durif A (1959) Structure cristalline des orthovanadates et orthoarseniates de baryum et de strontium. Acta Crystallogr 12:420–421

    Google Scholar 

  • Fix W, Heymann H, Heinke R (1969) Subsolidus relations in the system 2CaO SiO2-3CaO P2O5. J Am Cerm Soc 52:346–347

    Google Scholar 

  • Gopal R, Calvo C (1971) Crystal structure of Ca3 (AsO4)2. Can J Chem 49:1036–1046

    Google Scholar 

  • Gopal R, Calvo C (1972) Structural relationship of whitlockite and β-Ca3 (PO4)2. Nature Phys Sci 237:30–32

    Google Scholar 

  • Gopal R, Calvo C (1973) The structure of Ca3 (VO4)2. Z Kristallogr Mineral 137:67–85

    Google Scholar 

  • Griffin WL, Åmli R, Heier KS (1972) Whitlockite and apatite from lunar rock 14310 and from Ödegården, Norway. Earth Planet Sci Lett 15:53–58

    Google Scholar 

  • International Tables for X-ray Crystallography, Vol. IV (1974) Kynoch Press, Birmingham

  • Kawai N, Endo S (1970) The generation of ultrahigh hydrostatic pressures by a split sphere apparatus. Rev Sci Instrum 41:1178–1181

    Google Scholar 

  • Kumazawa M (1982) Origin of materials in the earth's interior and their layered distribution. In: Sunagawa I and Aoki K (ed) Material Science of the Earth's interior. J Jap Assoc Min Petr Econ Geol Collected papers: 293–310

  • McConnell D (1973) Apatite, Its Crystal Chemistry, Mineralogy, Utilization, and Geologic Occurrences. Springer, Wien New York, pp 22–38

    Google Scholar 

  • Murayama JK, Kato M, Nakai S, Kumazawa M (1986) A densepolymorph of Ca3 (PO4)2: a high pressure phase of apatite decomposition and its geochemical significance. Phys Earth Planet Inter 44:293–303

    Google Scholar 

  • Nurse RW, Welch JH, Gutt W (1959) High-temperature phase equilibria in the system dicalcium silicate-tricalcium phosphate. J Chem Soc 220:1077–1083

    Google Scholar 

  • O'Keeffe M (1979) A proposed rigorous definition of coordination number. Acta Crystallogr A35:772–775

    Google Scholar 

  • Onuma N, Hirano M, Isshiki M (1983) Genesis of basalt magmas and their derivatives under the Izu islands, Japan, inferred from Sr/Ca-Ba/Ca systematics. J Volcanol Geotherm Res 18:511–529

    Google Scholar 

  • Roux P, Louër D, Bonel G (1978) Sur nouvelle forme cristalline du phosphate tricalcique. C R Acad Sci Paris Ser C 286:549–551

    Google Scholar 

  • Sawamoto H (1986) Single crystal growth of the modified spinel (β) and spinel (γ) phases of (Mg, Fe)2SiO4 and some geophysical implications. Phys Chem Minerals 13:1–10

    Google Scholar 

  • Süsse P, Buerger MJ (1970) The structure of Ba3 (VO4)2. Z Kristallogr Mineral 131:161–174

    Google Scholar 

  • Takéuchi Y (1984) Sphere-packing model of atomic arrangements and coordination polyhedra in inorganic structures. Paul Niggli Symposium. Col Abst, Swiss Soc Cryst: 59–62

  • Takéuchi Y, Haga N (1984) Characterization of coordination polyhedra. Mineral J 12:83–86

    Google Scholar 

  • Wuensch BJ, Prewitt CT (1965) Corrections for x-ray absorption by a crystal of arbitrary shape. Z Kristallogr Mineral 122:24–59

    Google Scholar 

  • Zachariasen WH (1948) The crystal structure of the normal orthophosphates of barium and strontium. Acta Crystallogr 1:263–265

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sugiyama, K., Tokonami, M. Structure and crystal chemistry of a dense polymorph of tricalcium phosphate Ca3 (PO4)2: A host to accommodate large lithophile elements in the earth's mantle. Phys Chem Minerals 15, 125–130 (1987). https://doi.org/10.1007/BF00308774

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00308774

Keywords

Navigation