X-ray standing wave study of arsenite incorporation at the calcite surface

Likwan Cheng, Paul Fenter, Neil C. Sturchio*, Zhong Zhong, Michael J. Bedzyk

*Corresponding author for this work

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

The location and orientation of arsenite incorporated at the CaCO3 (1014) cleavage surface from a dilute aqueous solution was examined with the X-ray standing wave (XSW) technique. The high coherent fractions measured for As on the (1014) and (0006) Bragg reflections indicate that the arsenite was well ordered in registration with the calcite surface lattice. The As coherent positions show that arsenite was located at the carbonate site. The XSW analysis is consistent with a structural model in which the pyramidal-shaped arsenite ion was oriented with its oxygen base coincident with the carbonate plane, and its As apex pointing outward from the (1014) surface. The structure observed here for arsenite, and previously for selenite, suggests that other pyramidal trioxyanions could be incorporated at the calcite (1014) surface with the same geometry.

Original languageEnglish (US)
Pages (from-to)3153-3157
Number of pages5
JournalGeochimica et Cosmochimica Acta
Volume63
Issue number19-20
DOIs
StatePublished - Oct 1 1999

ASJC Scopus subject areas

  • Geochemistry and Petrology

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