Powder neutron diffraction studies of a carbonate fluorapatite

Journal Article · Tue Feb 01 04:00:00 EST 2000 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.2000.0076· OSTI ID:20216019

Leventouri, Th ^[1]; Chakoumakos, B C ^[2]; Moghaddam, H Y ^[1]; Perdikatsis, V ^[3]

---

1. Physics Department, Florida Atlantic University, Boca Raton, Florida 33431 (United States)
2. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States)
3. Institute of Geology and Mineral Exploration, Messogion 70, 11527 Athens, (Greece)

Atomic positional disorder of a single-phase natural carbonate fluorapatite (francolite) is revealed from analysis of the atomic displacement parameters (ADPs) refined from neutron powder diffraction data as a function of temperature and carbonate content. The ADPs of the francolite show a strong disturbance at the P, O3, and F sites. When it is heat treated to partially or completely remove the carbonate, the ADPs as well as the other structural parameters resemble those of a fluorapatite (Harding pegmatite) that was measured under the same conditions. The various structural changes are consistent with a substitution mechanism whereby the planar carbonate group replaces a phosphate group and lies on the mirror plane of the apatite structure. (c) 2000 Materials Research Society.

• OSTI ID: 20216019
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 2 Vol. 15; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM FLUORIDES
CALCIUM PHOSPHATES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
EXPERIMENTAL DATA
HEAT TREATMENTS
LATTICE PARAMETERS
NEUTRON DIFFRACTION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K