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

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Geochim. Cosmochim. Acta

DOI:https://doi.org/10.1016/S0016-7037(99)00242-2· OSTI ID:942590

Cheng, L; Fenter, P; Sturchio, N C; Zhong, Z; Bedzyk, M J; BNL,

The location and orientation of arsenite incorporated at the CaCO{sub 3} (10{bar 1} 4) 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 (10{bar 1} 4) 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 (10{bar 1} 4) surface. The structure observed here for arsenite, and previously for selenite, suggests that other pyramidal trioxyanions could be incorporated at the calcite (10{bar 1} 4) surface with the same geometry.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 942590
• Report Number(s): ANL/ER/JA-32801
• Journal Information: Geochim. Cosmochim. Acta, Journal Name: Geochim. Cosmochim. Acta Journal Issue: 19-20 ; Oct. 1999 Vol. 63; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
58 GEOSCIENCES
AQUEOUS SOLUTIONS
ARSENIC OXIDES
BRAGG REFLECTION
CALCITE
CLEAVAGE
CRYSTAL STRUCTURE
ORIENTATION
SORPTION
STANDING WAVES
SURFACE PROPERTIES
X RADIATION