Raman spectroscopy of various phosphate minerals and occurrence of tuite in the Elga IIE iron meteorite

Konstantin D. Litasov, Nikolay M. Podgornykh

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33 Citations (Scopus)

Abstract

The Raman spectra of phosphate minerals: apatite, merrillite, panethite, brianite, czochralskiite, maricite, new phosphate with composition of Na2Fe(Mg,Ca)(PO4)2 and high-pressure phase tuite from the Elga IIE iron meteorite are characterized. Panethite, brianite, czochralskiite and new Na-Fe phosphate were described for the first time. The basic features of all studied phosphates include strong ν1 symmetric stretching mode of PO4 3− ions at 950–990 cm−1, antisymmetric ν3 vibrations in the 1000–1175 cm−1 region and weak bands in the 400–500 cm−1 region, which correspond to ν2 bending mode and in the 550–640 cm−1 region, related to ν4 bending mode. Weak bands at less than 300 cm−1 represent lattice modes. Most of the studied phosphates have three non-equivalent positions of phosphorus atoms in the crystal structures and can be derived from glaserite, K3Na(SO4)2, arrangement. Two or three of non-equivalent [PO4] tetrahedra typically correspond to two or three strong bands in the region of ν1 vibrations. High-pressure mineral tuite has similar composition and was formed after merrillite. P-O vibrations in equivalent [PO4] tetrahedra produce major Raman band of tuite at 972 cm−1. The Elga parent-body experienced a shock pressure of at least 12–15 GPa according to minimum pressures of tuite formation in the static high-pressure experiments. This is the first finding of tuite in iron meteorites and the only second finding of high-pressure mineral in them.

Original languageEnglish
Pages (from-to)1518-1527
Number of pages10
JournalJournal of Raman Spectroscopy
Volume48
Issue number11
DOIs
Publication statusPublished - 1 Nov 2017

Keywords

  • apatite
  • iron meteorite
  • merrillite
  • phosphate
  • tuite
  • MERRILLITE
  • 6 GPA
  • CA3(PO4)2
  • STISHOVITE
  • CRYSTAL-CHEMISTRY
  • PRESSURE
  • WHITLOCKITE
  • PHASE
  • DENSE POLYMORPH
  • MARTIAN METEORITE

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