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Title: Synthesis and distribution of cations in substituted lead phosphate lacunar apatites

Abstract

Synthesis of apatites, Pb{sub 7.4}Bi{sub 0.3}Na{sub 2.3}(PO{sub 4}){sub 6} (I), Pb{sub 7.36}Bi{sub 0.32}Na{sub 2.08}Li{sub 0.24}(PO{sub 4}){sub 6} (II) and Pb{sub 5.78}Bi{sub 0.81}Ca{sub 0.60}Na{sub 2.81}(PO{sub 4}){sub 6} (III), with anion vacancy were carried out during solid state reactions. The three compounds of apatite-type structure crystallize in the hexagonal system, space group P6{sub 3}/m. In every compound, a preferential occupation of the (6h) site by Pb and Bi cations is shown revealing the influence of their lone electronic pair. The introduction of calcium increases the quantity of bismuth in these apatites. Alkaline metals occupy mainly the (4f) site. Infrared spectroscopy is correlated to the bonding scheme. A connection between the cations occupying (4f) sites and the c cell parameters is presented.

Authors:
 [1];  [2];  [2];  [1];  [3];  [1]
  1. Laboratoire de Sciences des Materiaux et d'Environnement, Faculte des Sciences de SFAX, BP 802, 3018 SFAX (Tunisia)
  2. (France)
  3. Centre d'Elaboration de Materiaux et d'Etudes Structurales, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex 4 (France) and Universite Paul SABATIER, 118 Route de Narbonne, 31400 Toulouse (France). E-mail: savariau@cemes.fr
Publication Date:
OSTI Identifier:
21000591
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 42; Journal Issue: 2; Other Information: DOI: 10.1016/j.materresbull.2006.05.027; PII: S0025-5408(06)00236-4; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; APATITES; BISMUTH; CALCIUM; CATIONS; CHEMICAL PREPARATION; DEFECTS; HEXAGONAL LATTICES; INFRARED SPECTRA; INORGANIC COMPOUNDS; LEAD PHOSPHATES; SPACE GROUPS; VACANCIES; X-RAY DIFFRACTION

Citation Formats

Hamdi, Besma, Centre d'Elaboration de Materiaux et d'Etudes Structurales, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex 4, Universite Paul SABATIER, 118 Route de Narbonne, 31400 Toulouse, Feki, Hafed El, Savariault, Jean-Michel, and Salah, Abdelhamid Ben. Synthesis and distribution of cations in substituted lead phosphate lacunar apatites. United States: N. p., 2007. Web. doi:10.1016/j.materresbull.2006.05.027.
Hamdi, Besma, Centre d'Elaboration de Materiaux et d'Etudes Structurales, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex 4, Universite Paul SABATIER, 118 Route de Narbonne, 31400 Toulouse, Feki, Hafed El, Savariault, Jean-Michel, & Salah, Abdelhamid Ben. Synthesis and distribution of cations in substituted lead phosphate lacunar apatites. United States. doi:10.1016/j.materresbull.2006.05.027.
Hamdi, Besma, Centre d'Elaboration de Materiaux et d'Etudes Structurales, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex 4, Universite Paul SABATIER, 118 Route de Narbonne, 31400 Toulouse, Feki, Hafed El, Savariault, Jean-Michel, and Salah, Abdelhamid Ben. Thu . "Synthesis and distribution of cations in substituted lead phosphate lacunar apatites". United States. doi:10.1016/j.materresbull.2006.05.027.
@article{osti_21000591,
title = {Synthesis and distribution of cations in substituted lead phosphate lacunar apatites},
author = {Hamdi, Besma and Centre d'Elaboration de Materiaux et d'Etudes Structurales, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex 4 and Universite Paul SABATIER, 118 Route de Narbonne, 31400 Toulouse and Feki, Hafed El and Savariault, Jean-Michel and Salah, Abdelhamid Ben},
abstractNote = {Synthesis of apatites, Pb{sub 7.4}Bi{sub 0.3}Na{sub 2.3}(PO{sub 4}){sub 6} (I), Pb{sub 7.36}Bi{sub 0.32}Na{sub 2.08}Li{sub 0.24}(PO{sub 4}){sub 6} (II) and Pb{sub 5.78}Bi{sub 0.81}Ca{sub 0.60}Na{sub 2.81}(PO{sub 4}){sub 6} (III), with anion vacancy were carried out during solid state reactions. The three compounds of apatite-type structure crystallize in the hexagonal system, space group P6{sub 3}/m. In every compound, a preferential occupation of the (6h) site by Pb and Bi cations is shown revealing the influence of their lone electronic pair. The introduction of calcium increases the quantity of bismuth in these apatites. Alkaline metals occupy mainly the (4f) site. Infrared spectroscopy is correlated to the bonding scheme. A connection between the cations occupying (4f) sites and the c cell parameters is presented.},
doi = {10.1016/j.materresbull.2006.05.027},
journal = {Materials Research Bulletin},
number = 2,
volume = 42,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • Bismuth substituted apatites of two general types have been prepared: M/sub 10-2x/Bi/sub x/Na/sub x/(PO/sub 4/)/sub 6/Y/sub 2/ (M = Ca, Sr, Pb; Y = F, Cl) and lead apatites with the Y ion completely vacant Pb/sub 10-(2x +2)/Bi/sub x/Na/sub x+2/(PO/sub 4/)/sub 6/. X-ray powder diffraction patterns of all the compounds show the P6/sub 3//m hexagonal apatite type structure. The change of the lattice parameters and c/a values with compositions indicate the preference of the bismuth ions to occupy the 6h triangular positions. Bi/sup 3 +/ tends to incorporate in apatites with unoccupied halide positions.
  • Cadmium substituted strontium hydroxy- and fluoro-apatites, Sr{sub (10-x)}Cd{sub x}(PO{sub 4}){sub 6}Y{sub 2} (Y = OH and F), have been prepared as single phases in the 0 {<=} x {<=} 4 interval for the former and 0 {<=} x {<=} 6 for the latter compound, respectively. The refinements of the X-ray full powder patterns allowed the structure determination of nine samples, and showed a preference of cadmium atoms for the M(1) site in fluoroapatite samples. IR investigation gave information about the nature of the metal oxygen interactions. The obtained results are used for a comparative discussion about the factors which drivemore » the mutual substitution of Ca, Sr, Cd and Pb in apatites. The important role of electronegativity and polarisability, as well as of ionic radii, is evidenced.« less
  • This study was aimed at the investigation of the thermal stability of Mg-substituted carbonated apatites over the wide temperature range. Two different apatites were studied, which were prepared by either precipitation from aqueous solution or by solid-liquid interaction. The following methods were employed: FTIR spectroscopy of the condensed gas phase to evaluate the CO and CO{sub 2} release with increasing temperature, FTIR of the solid residue after heating, XRD analysis, thermogravimetry and scanning electron microscopy. Decomposition behavior was shown to depend significantly on the synthesis method. Wet-synthesized powders are significantly less thermally stable compared with those prepared by solid-liquid interaction.more » Intensive release of carbon oxides from the former was observed at 300 deg. C, whereas the latter powder was relatively stable up to temperature about 1000 deg. C.« less
  • The pyridinium cations within betaines can be aminated under mild conditions with aqueous ammonia, ultimately undergoing cyclization to a new tricyclic system: 4-substituted-3,5-dioxopyrimido(5,6-c)-1'-azaquinolizine. Intermediates in the reaction are 4-substituted-3,5-dioxo-2,2-dihydropyrimido(5,6-c)-6H-1'-quinolizines. Formation of the methylene group is coupled with transfer of an atom of hydrogen or deuterium from the ..cap alpha..-carbon of the dihydropyridine in compound II to the carbon atom of the azomethine group. The NMR spectrum is represented by the methylene proton signal (3.96 ppm) and by the multiplets of the pyridine and phenyl protons centered at 7.63 and 6.38 ppm respectively. Upon chloranil oxidation, and upfield shift of themore » pyridine protons is observed: the ..cap alpha..-proton forms a doublet (10.05 ppm, J= 6 Hz), the ..beta..-protons form a doublet and a triplet with centers at 8.57 (J = 8 Hz) and 8.22 (J = 7 Hz) ppm respectively, and the ..gamma..-proton forms a triplet at 8.8 (J = 7 Hz) ppm.« less
  • Cyclopentane-1,3-diyl radical cations were generated from the 1-methyl- and 1,4-dimethyl substituted bicyclo-[2.1.0]pentanes 1b,c through photoinduced electron transfer (PET) and radiolytic oxidation. The unsymmetrical bridgehead-substituted bicyclopentane 1b rearranged spontaneously and exclusively to the 3-methylcyclopentene 3b under PET conditions. ESR studies showed similarly that 3b[sup [sm bullet]+] was the only final oxidation product of 1b; the initial radical cation 1b[sup [sm bullet]+] was not detected because it rearranges rapidly and stereoselectively by a 1,2-hydrogen shift to 3b[sup [sm bullet]+], even at 80 K, and no trace of the more stable 1-methylcyclopentene radical cation 3a[sup [sm bullet]+] was observed. This contra-thermodynamic regioselectivity ismore » rationalized in terms of essential localization of positive charge at the tertiary center as the reaction proceeds in the 1,3-diyl radical cation 1b[sup [sm bullet]+]. The symmetrical dimethyl derivative 1c rearranged much more reluctantly than 1b despite its lower oxidation potential, and this is attributed to the greater persistence of radical cation 1c[sup [sm bullet]+] through its reluctance to undergo a 1,2-H shift. The oxidation of these azoalkanes generates highly reactive transients, presumably diazenyl radical cations, which readily denitrogenate and undergo 1,2-H shifts in either a consecutive or concerted manner to form olefin radical cations. 25 refs., 6 figs., 2 tabs.« less