The high-pressure crystal chemistry of low albite and the origin of the pressure dependency of Al-Si ordering

Robert T Downs, R. M. Hazen, L. W. Finger

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

Structural and volume compressibility data for low albite were obtained by single-crystal X-ray diffraction methods at pressures up to ~4 GPa. The bulk modulus was determined to be 54(1) GPa, with a pressure derivative of 6(1). Intensity data were collected, and structures were refined at 0.00, 0.44, 1.22, 2.68, and 3.78 GPa. With increasing pressure, (1) the volumes of the TO4 tetrahedra do not vary, (2) the volume of the NaO7 polyhedron varies linearly with the volume of the unit cell and (3) Si-O-Si angles increase or remain constant, but only Al-O-Si angles decrease, which is consistent with the smaller force constant of the Al-O-Si vs. Si-O-Si angle. It is concluded that compression is accomplished through the bending of Al-O-Si angles, which squeezes together the chains of four-membered rings that run parallel to [001] and that are separated by zigzag channels containing Na atoms. -from Authors

Original languageEnglish (US)
Pages (from-to)1042-1052
Number of pages11
JournalAmerican Mineralogist
Volume79
Issue number11-12
StatePublished - 1994
Externally publishedYes

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Crystal chemistry
crystal chemistry
albite
chemistry
crystals
Compressibility
bulk modulus
Elastic moduli
polyhedrons
compressibility
Single crystals
tetrahedrons
Derivatives
X ray diffraction
Atoms
X-ray diffraction
compression
crystal
rings
single crystals

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

The high-pressure crystal chemistry of low albite and the origin of the pressure dependency of Al-Si ordering. / Downs, Robert T; Hazen, R. M.; Finger, L. W.

In: American Mineralogist, Vol. 79, No. 11-12, 1994, p. 1042-1052.

Research output: Contribution to journalArticle

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