Structural modifications of hydroxyapatite induced by lead substitution for calcium

Bigi, Adriana; Gandolfi, Maria Teresa; Gazzano, Massimo; Ripamonti, A.; Roveri, Norberto; Thomas, S. A.

doi:10.1039/dt9910002883

Cited by 66 publications

(51 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, magnesium promotes the thermal conversion of HA into 13-TCP, where it can partially replace calcium (Bigi et al, 1988;Bigi et al, 1992;Bigi et al, 1993). The modifications of the values of the HA lattice constants induced by ionic substitution are generally in agreement with the difference in ionic radii between calcium and substituent ions (Heijligers, Driessens & Verbeck, 1979;Bigi, Gazzano, Ripamonti, Foresti & Roveri 1986;Bigi et al, 1989;Bigi et al, 1991). The poor resolution of the X-ray pattern of the apatitic phase synthesized in the presence of magnesium prevents an accurate determination of the lattice constant values and therefore does not allow to estabilish the extent of magnesium substitution for calcium (Bigi et al, 1993).…”

Section: Introductionsupporting

confidence: 50%

“…The incorporation of cations other than Ca 2+ into the HA structure generally provokes a decrease in its stability (Heijligers, Driessens & Verbeck, 1979;Le Geros & Le Geros, 1984;Baravelli, Bigi, Foresti, Ripamonti & Roveri, 1984;Bigi, Gazzano, Ripamonti, Foresti & Roveri, 1986;Bigi et al, 1991). The destabilizing effect of some ions, such as Mg 2÷, Mn 2÷, Fe 2÷, Co 2÷ and Ni 2÷, is so evident that they inhibit the synthesis of HA, promoting the formation of ~-tricalcium phosphate [/3-TCP (Le Geros, Taheri, Quirolgico & Le Geros, 1980;Nancollas, 1982)].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rietveld structure refinements of calcium hydroxylapatite containing magnesium

Bigi¹,

Falini²,

Foresti³

et al. 1996

Acta Crystallogr B Struct Sci

103

View full text Add to dashboard Cite

The crystal structures of four hydroxylapatite (HA) samples prepared from solutions in the presence of 10, 15, 25 and 30 Mg-atom-% have been investigated by X-ray powder pattern fitting. The total magnesium content of the solid samples, as determined by chemical analysis, was 4.9, 14.1, 20.4 and 30.6 Mg-atom-%, respectively. Rietveld analysis was performed using the computer program PREFIN implemented with routines which allow the refinements of the average crystallite sizes. Different refinement procedures were carried out in order to evaluate the effect of the amorphous and background profiles on the occupancy factor data. For comparison, magnesium-free hydroxylapatite was refined with the same strategies. The results of the different approaches indicate that the degree of magnesium substitution for calcium in the HA structure can be at most ,-~ 10 atom-%. Magnesium substitutes calcium preferentially at the 6(h) site. The broadening of the diffraction peaks increases on increasing the total magnesium content in the solid phase, which is always significantly higher than the amount incorporated into the HA structure. The excess is probably located in the amorphous phase and/or on the crystallite surface.

show abstract

Section: Introductionsupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Rietveld structure refinements of calcium hydroxylapatite containing magnesium

Bigi¹,

Falini²,

Foresti³

et al. 1996

Acta Crystallogr B Struct Sci

103

View full text Add to dashboard Cite

show abstract

“…Particularly the cell parameter c changes more for phases reach in lead. These results are in agreement with those reported previously (Bigi et al 1991, Hadrich et al 2001. A shift of band position is also observed in both FTIR and Raman spectra.…”

supporting

confidence: 83%

“…A complete solid solution between hydroxylapatite (HAP) and hydroxylpyromorphite (HPY) was determined before (Bigi et al 1991, Hadrich et al 2001. The results, however, are still fragmentary.…”

mentioning

confidence: 99%

Synthesis and mineralogical characteristics of hydroxylapatite-hydroxylpyromorphite solid solution series Ca5(PO4)3OH–Pb5(PO4)3OH

Motyka¹,

Oknińska²,

Manecki³

2015

geol

View full text Add to dashboard Cite

“…Bigi et al [4] Bigi et al [4]also prepared the Ca-Pb HA solid solutions by solid state reaction at 900°C and aqueous reaction at 100°C. The authors reported that the cell parameters a of the apatitic phase obtained by solid state reaction varied linearly with compositions, while the variation of the cell parameter c showed a discontinuity at about 50 Pb atom %.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic study of lead-substituted hydroxyapatite synthesized by high-temperature mixing method under hydrothermal conditions

Zhu

Qiu

et al. 2010

Inorganica Chimica Acta

View full text Add to dashboard Cite

Abstract:The solid solutions in the system of Ca and Pb hydroxyapatite, Ca 10-χ Pb χ HA (χ= 0-10), were successfully synthesized by high-temperature mixing method (HTMM) at 200ºC for 12 hours under hydrothermal conditions. The samples were characterized by X-ray diffraction, chemical analysis and electron microscopic observation, and the site of the metal ions in the solid solutions was analyzed with the Rietveld method.The lattice parameters of the solid solutions prepared by both of the methods didn't vary linearly with Pb contents, and they have two turning points of 0.4 and 0.6 of Pb content. It was found that Pb ions in the solid solutions preferentially occupied the M (2) site in the apatite structure. HTMM gives Ca-Pb HA solid solutions much better crystallization. However, due to the formation of intermediate compound of

show abstract

Structural modifications of hydroxyapatite induced by lead substitution for calcium

Cited by 66 publications

References 9 publications

Rietveld structure refinements of calcium hydroxylapatite containing magnesium

Rietveld structure refinements of calcium hydroxylapatite containing magnesium

Synthesis and mineralogical characteristics of hydroxylapatite-hydroxylpyromorphite solid solution series Ca5(PO4)3OH–Pb5(PO4)3OH

Crystallographic study of lead-substituted hydroxyapatite synthesized by high-temperature mixing method under hydrothermal conditions

Contact Info

Product

Resources

About