The effect of type-B carbonate content on the elasticity of fluorapatite

Abstract

The mechanical behavior of carbonate-bearing fluorapatite (CFAP) (with up to 5.5 wt% CO ) was investigated at high pressure up to 7 GPa. (Framont region, France). Preliminary characterization at ambient conditions was done by single-crystal X-ray diffraction study. The structure refinements, in space group P6 /m, confirm a type-B substitution of the phosphate (PO ) group by the carbonate ion (CO ) . The site occupancies for the C atom are 0.04 for FOW and 0.11 for FRA CFAP, in quite good agreement with the 1.6 and 5.5 wt% CO amount obtained by analytical methods. Single-crystal high-pressure XRD study on the two type-B CFAP samples was performed. The FOW and FRA crystals were mounted concurrently in a ETH-type DAC and cell parameters were determined at 26 different pressures up to 6.86 GPa at room T. The variation with pressure of the unit-cell parameters and volume shows no discontinuity that could be related to any possible phase transition in the P range investigated. The linear compressibility coefficients are β = 3.63 × 10 GPa and β = 2.47 × 10 GPa for FOW, and β = 3.67 × 10 GPa and β = 2.65 × 10 GPa for FRA, giving an axial anisotropy of β :β = 1.47:1 and 1.38:1, respectively. The P-V data were fitted by a second-order Birch-Murnaghan EoS and the resulting BM2-EoS coefficients are V = 519.81(7) Å , K = 92.1(3) GPa for FOW, and V = 518.95(9) Å , K = 89.1(4) GPa for FRA CFAP. The results obtained indicate that a 5.5 wt% CO content (type-B) reduces the isothermal bulk modulus by about 9%.

Raman Spectroscopy: In Vivo Application for Bone Evaluation in Oral Reconstructive (Regenerative) Surgery

“…The two sites for carbonate substitution in apatite each control the crystal's perfection and crystallite size, according to different environmental conditions. The B-type carbonate is specific for apatite formation of biominerals under physiological conditions [20,21].…”

Fossil Bioapatites with Extremely High Concentrations of Rare Earth Elements and Yttrium from Deep-Sea Pelagic Sediments

“…Bioapatites display a broad peak at 1430 cm –1 assigned to the ν 3 CO 3 band (Figure S9a). − This peak is absent in the Durango apatite which is magmatic-hydrothermal (Figure S9b). Sulfur, which was not measured, typically amounts to less than 2.0 wt % in bioapatite from deep-sea pelagic sediments. ,,, Notwithstanding the exact reasons for the deviation of the chemical sums from 100 wt % total, a plot of the concentrations of the four REY detected by EPMA (Y, La, Ce, Nd) and their concentrations measured by LA-ICP-MS shows excellent agreement between the two analyses (Table S7 and Figure S10, R 2 = 0.996).…”

“…Bioapatites display a broad peak at 1430 cm -1 assigned to the ν3 CO3 band (Figure S9a). [90][91][92][93] This peak is absent in the Durango apatite which is magmatichydrothermal 94 (Figure S9b). Sulfur, which was not measured, typically amounts to less than 2.0 wt % in bioapatite from deep-sea pelagic sediments.…”

Single-crystal X-ray diffraction of fluorapatite to 61 GPa

“…An area of interest has centered around the effects of substitution of anions that reside in the halogen site, and how solid solution affects the site location (Murayama et al 1986;Hughes et al 1989Hughes et al , 2014. A number of studies have also been conducted to characterize apatite's structural behavior and phase stability at high pressure (Brunet et al 1999;Comodi et al 2001;Matsukage et al 2004;Konzett and Frost 2009;Konzett et al 2012;Cámara et al 2018). Previous studies have shown that fluorapatite persists to 18.3 GPa at room temperature, but decomposes into an assemblage containing tuite, γ-Ca 3 (PO 4 ) 2 , at ~12 GPa and temperatures above 1000°C (Sugiyama and Tokonami 1987;Matsukage et al 2004).…”