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

K. Sugiyama, M. Tokonami

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)125-130
Number of pages6
JournalPhysics and Chemistry of Minerals
Volume15
Issue number2
DOIs
Publication statusPublished - 1987 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Structure and crystal chemistry of a dense polymorph of tricalcium phosphate Ca<sub>3</sub> (PO<sub>4</sub>)<sub>2</sub>: A host to accommodate large lithophile elements in the earth's mantle'. Together they form a unique fingerprint.

Cite this