Abstract
Sodium-bearing, type A-B carbonate fluorapatites {Ca10-1.5yNay□0.5y[(PO4)6-2y(CO3)2y][F2-2x(CO3)x], with x ≈ y ≈ 0.1; CFAP} have been synthesized at 1150-1300 °C and 1.0 GPa, and investigated by single-crystal X-ray diffraction and FTIR spectroscopy. Typical crystal and compositional data are a = 9.3659(3), c = 6.8901(4) Å, space group P63/m, R = 0.023, Rw = 0.021, x = 0.14(3), and 2y = 0.23(1). Crystal-chemical features and FTIR spectra are similar to Na-bearing, type A-B carbonate hydroxylapatites (CHAP) reported recently. However, uptake of carbonate is significantly lower in CFAP than in CHAP for similar conditions of crystal synthesis. Structural accommodation of the substitutions requires local coupling of the Na cation and channel (type A) and phosphate (type B) carbonate ion defects, as in CHAP but now in the approximate ratio 1:1:2. The type B carbonate ion is located on the sloping faces of the substituted phosphate group, and tilted only 3.5° from the mirror plane. The presence of weak electron density in the outer wall of the c-axis channel of apatite and in triangular coordination with one Ca1 and two Ca2 cations appears to represent a trace amount of excess fluoride, the controversial crystal-chemical feature of francolite.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Hydrothermal synthesis of hematite spherules and jarosite: Implications for diagenesis and hematite spherule formation in sulfate outcrops at Meridiani Planum, Mars
- Concentric slow cooling of a low-P–high-T terrane: Evidence from 1600–1300 Ma mica dates in the 1780–1700 Ma Black Hills Orogen, South Dakota, U.S.A.
- Monazite ages from carbonatites and high-grade assemblages along the Kambam Fault (Southern Granulite Terrane, South India)
- Forward modeling of the effects of mixed volatile reaction, volume diffusion, and formation of submicroscopic exsolution lamellae on calcite-dolomite thermometry
- A low-temperature phase diagram for ilmenite-rich compositions in the system Fe2O3-FeTiO3
- Dehydrogenation of kaersutitic amphibole under electron beam excitation recorded by changes in Fe3+/ΣFe: An EMP and SIMS study
- Protonation in germanium equivalents of ringwoodite, anhydrous phase B, and superhydrous phase B
- Andreyivanovite: A second new phosphide from the Kaidun meteorite
- The crystal chemistry of whitlockite and merrillite and the dehydrogenation of whitlockite to merrillite
- Single-crystal elastic properties of (Mg0.987,Fe0.013)O to 9 GPa
- Stoichiometry of synthetic ulvöspinel single crystals
- Thermal behavior and structural transformation in the chabazite-type zeolite willhendersonite, KCaAl3Si3O12·5H2O
- The kinetics and mechanisms of schwertmannite transformation to goethite and hematite under alkaline conditions
- Crystal chemistry of the mixed-layer sequence talc–talc-smectite–smectite from submarine hydrothermal vents
- Crystal chemical and structural characterization of fibrous tremolite from Susa Valley, Italy, with comments on potential harmful effects on human health
- Thermodynamic properties of CaTh(PO4)2 synthetic cheralite
- A computational study of order-disorder phenomena in Mg2TiO4 spinel (qandilite)
- Mineralogical characterization of silica sinters from the El Tatio geothermal field, Chile
- Influence of multi-electron excitation on EXAFS spectroscopy of trivalent rare-earth ions and elucidation of change in hydration number through the series
- Pressure-induced over-hydration and water ordering in gismondine: A synchrotron powder diffraction study
- 57Fe Mössbauer study of the oxidation state of iron in stilpnomelane from granite pegmatites in Poland
- Constraints on structural models of ferrihydrite as a nanocrystalline material
- Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation
- Equation of state and crystal structure of a new germanate post-titanite phase
- Synthetic hypersilicic Cl-bearing mica in the phlogopite-celadonite join: A multimethodical characterization of the missing link between di- and tri-octahedral micas at high pressures
- The effect of crystal-melt partitioning on the budgets of Cu, Au, and Ag
- Thermodynamics of dehydration in analcime: Absorption calorimetry and equilibrium observations
- Accommodation of the carbonate ion in fluorapatite synthesized at high pressure
- Unusual Al-Si ordering in calcic scapolite, Me79.6, with increasing temperature
- Letter. Identification of randomly interstratified illite/smectite with basal peak widths
Articles in the same Issue
- Hydrothermal synthesis of hematite spherules and jarosite: Implications for diagenesis and hematite spherule formation in sulfate outcrops at Meridiani Planum, Mars
- Concentric slow cooling of a low-P–high-T terrane: Evidence from 1600–1300 Ma mica dates in the 1780–1700 Ma Black Hills Orogen, South Dakota, U.S.A.
- Monazite ages from carbonatites and high-grade assemblages along the Kambam Fault (Southern Granulite Terrane, South India)
- Forward modeling of the effects of mixed volatile reaction, volume diffusion, and formation of submicroscopic exsolution lamellae on calcite-dolomite thermometry
- A low-temperature phase diagram for ilmenite-rich compositions in the system Fe2O3-FeTiO3
- Dehydrogenation of kaersutitic amphibole under electron beam excitation recorded by changes in Fe3+/ΣFe: An EMP and SIMS study
- Protonation in germanium equivalents of ringwoodite, anhydrous phase B, and superhydrous phase B
- Andreyivanovite: A second new phosphide from the Kaidun meteorite
- The crystal chemistry of whitlockite and merrillite and the dehydrogenation of whitlockite to merrillite
- Single-crystal elastic properties of (Mg0.987,Fe0.013)O to 9 GPa
- Stoichiometry of synthetic ulvöspinel single crystals
- Thermal behavior and structural transformation in the chabazite-type zeolite willhendersonite, KCaAl3Si3O12·5H2O
- The kinetics and mechanisms of schwertmannite transformation to goethite and hematite under alkaline conditions
- Crystal chemistry of the mixed-layer sequence talc–talc-smectite–smectite from submarine hydrothermal vents
- Crystal chemical and structural characterization of fibrous tremolite from Susa Valley, Italy, with comments on potential harmful effects on human health
- Thermodynamic properties of CaTh(PO4)2 synthetic cheralite
- A computational study of order-disorder phenomena in Mg2TiO4 spinel (qandilite)
- Mineralogical characterization of silica sinters from the El Tatio geothermal field, Chile
- Influence of multi-electron excitation on EXAFS spectroscopy of trivalent rare-earth ions and elucidation of change in hydration number through the series
- Pressure-induced over-hydration and water ordering in gismondine: A synchrotron powder diffraction study
- 57Fe Mössbauer study of the oxidation state of iron in stilpnomelane from granite pegmatites in Poland
- Constraints on structural models of ferrihydrite as a nanocrystalline material
- Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation
- Equation of state and crystal structure of a new germanate post-titanite phase
- Synthetic hypersilicic Cl-bearing mica in the phlogopite-celadonite join: A multimethodical characterization of the missing link between di- and tri-octahedral micas at high pressures
- The effect of crystal-melt partitioning on the budgets of Cu, Au, and Ag
- Thermodynamics of dehydration in analcime: Absorption calorimetry and equilibrium observations
- Accommodation of the carbonate ion in fluorapatite synthesized at high pressure
- Unusual Al-Si ordering in calcic scapolite, Me79.6, with increasing temperature
- Letter. Identification of randomly interstratified illite/smectite with basal peak widths