Structure refinements by the Rietveld method of partially substituted hydroxyapatite: Ca9Na0.5(PO4)4.5(CO3)1.5(OH)2

Feki, Hafed El; Savariault, Jean‐Michel; Salah, Abdelhamid Ben

doi:10.1016/s0925-8388(99)00070-5

Cited by 122 publications

(87 citation statements)

References 27 publications

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“…The inset in Figure 7a shows higher magnification of the region between 800 and 1200 cm −1 with the main band (mode ν 1 of PO 4 ) of HAP at 1020 cm −1 . As follows from the inset, the band in the spectra of the examined samples matches well that appearing in the standard HAP spectrum; there is no displacement, however for higher pH (8 and 9) a low frequency shoulder occurs, which may be assigned to the partial substitution of calcium ions by other cations [36,37]. The IR spectra of the samples obtained from the artificial urine of normal composition of artificial urine (with magnesium chloride hexahydrate) were also measured.…”

Section: Ir Analysissupporting

confidence: 59%

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Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

et al. 2018

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Magnesium ammonium phosphate hexahydrate, called struvite, is the dominant component of infectious urinary stones. In addition to struvite, infectious urinary stones include solid phases with poor crystallinity as well as amorphous matter. This article is devoted to the analysis of these solid phases, because they have not been characterized well until now. The solid phases tested were obtained from artificial urine in the absence and presence of Proteus mirabilis. The solid phases were characterized by different techniques (X-ray Diffraction, Energy Dispersive X-ray, Scanning Electron Microscopy, as well as Raman and Infrared Spectroscopies). According to the results these phases are carbonate apatite (CA), hydroxylapatite (HAP), amorphous calcium carbonate (ACC), amorphous calcium phosphate (ACP) and/or amorphous carbonated calcium phosphate (ACCP). Carbonate apatite and hydroxylapatite may occur in non-stoichiometric forms, i.e., various anions can be substituted for CO 3 2− , OH − , and PO 4 3− groups in them. The non-stoichiometry of carbonate apatite and hydroxylapatite also implies a deficiency of calcium ions, i.e., calcium ions may be partially replaced by other cations. Experimental techniques and chemical speciation analysis demonstrate that the presence of magnesium influences the formation of CA and HAP.

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Section: Ir Analysissupporting

confidence: 59%

“…This type of hydroxylapatite substitution has already been described in Refs. [36,37]. However, it should be pointed out that in this case, a very characteristic halo (Figure 3b, arrow) is also seen indicating that part of the sample is in amorphous form.…”

Section: Non-modified Composition Of Artificial Urine Ph Increase Inmentioning

confidence: 71%

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

et al. 2018

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“…3, Table 1). Powder XRD measurements display that the changes in the apatite composition lead to deformations of the apatite structure along the hexagonal axis [4,14]. The deformations are related to partial substitution of PO 4 by CO 3 and F -by OH -and/or CO 3 .…”

Section: Resultsmentioning

confidence: 99%

Structural and thermal transformations on high energy milling of natural apatite

Petkova

Koleva

Kostova

et al. 2014

J Therm Anal Calorim

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In this work we investigated the isomorphic substitution and thermal decomposition of sedimentary fluor apatite (FAp) (with Ca/P ratio [ 1.67) from Tunisia after high-energy-milling (HEM) activation at different times from 10 to 600 min. The chemical composition of the material includes: 29.6 % P 2 O 5 total and 46.5 % CaO (main components) and 3.5 % F; 0.55 % R 2 O 3 (R = Al, Fe); 1.1 % SO 3 ; 1.9 % SiO 2 (a low content in a comparison with other natural apatites from North Africa or Asia); 0.35 % MgO; 0.05 % Cl; 6.6 % CO 2 are impurities. HEM is a well-known approach for preparing various solid materials and for increasing their reactivity. The solid-state transformation of the initial and HEM-activated apatite samples was examined by chemical analysis, BET, powder XRD, FTIR spectroscopy, and thermal analysis. The structure of natural apatite allows isomorphic substitutions of carbonate, hydroxyl, and metal ions by PO 4 3-, Ca 2? , and F -. The obtained powder XRD data indicate an increased defectiveness of the apatite structure in the course of the HEM. The solid-state transformations of the initial and HEM-activated apatite are examined by TG-DTA analyses. It is found that the thermal stability of the activated samples decreases as compared to the initial sample. This is related to the increased defectivity of the apatite structure during the high-energy milling shown by the XRD data. The thermal analysis allows the differentiation of the structurally bonded A, B, and A-B types carbonate ions from these originating from the calcite and dolomite admixtures. The results obtained demonstrate that the mechanical distortion and the structural changes related to the migration of the carbonate ions from B type to A-type channel positions are the main factors responsible for the enhanced solubility of the high-energy activated FAp.

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“…• disappear due to the incorporation of CO V Ca + 3CO 2− 3 + Na + [10,26,27], where V X represents a vacancy on a regular apatite lattice site; thus the proposed chemical formula of the product is Ca 10− 2x 3 [10,26]. The higher limit of 3 corresponds to the theoretical solubility limit of 22.3 wt% of carbonate in HAP [2].…”

Section: The Product Of the Reactionmentioning

confidence: 99%

Calorimetric investigation of reaction Ca(NO₃)₂ + Na₃PO₄ in water and microemulsions saturated with CO₂

Du¹,

An²,

Fan³

et al. 2011

Int J of Chemical Kinetics

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The reactions of Ca(NO 3 ) 2 + Na 3 PO 4 in water and water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/hydrocarbon microemulsions saturated CO 2 with various molar ratios of water to surfactant R, oil phases, and surfactant concentrations were investigated by isothermal titration calorimetry. The product of the reaction was confirmed to be sodium-and-carbonatesubstituted hydroxyapatite (NaCO 3 HAP) by Fourier transform infrared spectra (FTIR), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). From calorimetric measurements, the molar enthalpies of solution of water in the AOT/n-dodecane system, and the molar enthalpies, the rate constants, and the activation energies of the reactions were determined. It was found that the enthalpy of solution of water in AOT/n-dodecane micells and the molar enthalpy of the reaction in the microemulsions increased with the decreases of R until R = 7; below that they kept almost constant. It may be attributed to the increase of the ratio of the bound water to the free water with the decrease of R until there was no free water when R < 7. However, the reaction rate constant k 1 was affected by the ionic strength of the medium and log k 1 showed a linear dependence on 1/R in the whole range of R we investigated. It was also observed that the rate constant and the enthalpy of the reaction remained almost unchanged when the surfactant concentration and the nature of oil phase varied. C

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Structure refinements by the Rietveld method of partially substituted hydroxyapatite: Ca9Na0.5(PO4)4.5(CO3)1.5(OH)2

Cited by 122 publications

References 27 publications

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

Structural and thermal transformations on high energy milling of natural apatite

Calorimetric investigation of reaction Ca(NO₃)₂ + Na₃PO₄ in water and microemulsions saturated with CO₂

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Structure refinements by the Rietveld method of partially substituted hydroxyapatite: Ca9Na0.5(PO4)4.5(CO3)1.5(OH)2

Cited by 122 publications

References 27 publications

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

Solid Phases Precipitating in Artificial Urine in the Absence and Presence of Bacteria Proteus mirabilis—A Contribution to the Understanding of Infectious Urinary Stone Formation

Structural and thermal transformations on high energy milling of natural apatite

Calorimetric investigation of reaction Ca(NO3)2 + Na3PO4 in water and microemulsions saturated with CO2

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Calorimetric investigation of reaction Ca(NO₃)₂ + Na₃PO₄ in water and microemulsions saturated with CO₂