A new possible atomic arrangement for the carbon atom in the B-sites of AB-type carbonate apatite
AUTOR(ES)
Araújo, Jorge Correa de, Moreira, Elizabeth Lima, Moraes, Valeria Conde Alves, Moreira, Ana Paula Duarte, Soares, Glória Dulce de Almeida
FONTE
Materials Research
DATA DE PUBLICAÇÃO
26/08/2011
RESUMO
The crystal structure of a synthetic AB-type carbonate apatite sample was analyzed by Rietveld refinement including a model with carbon atom not fixed in the B-site of the apatite structure. Only one constraint was applied to this model: the fractional occupancies of the atoms in the CO3 ion plus PO4 ion were equal 1.0 per phosphate site with six sites per unit cell. Rietveld refinement of the crystal structure with space group P6(3)/m results in cell parameters a = 9.3583(1) Å and c = 6.9226(5) Å; Z =1; Rwp = 0.0824 and 9.5 wt. (%) of carbonate in this structure. The use of simple geometry formulas showed that the C atom is not located at the center of the equilateral triangle of oxygen O2, O3 and O3', but to a distance 0.18 Å of this triangle. The results seem to indicate a new 3-D crystal structure of the carbonated apatite in PO4 groups.
Documentos Relacionados
- A NONENZYMATIC ILLUSTRATION OF “CITRIC ACID TYPE” ASYMMETRY: THE MESO-CARBON ATOM*
- A NONENZYMATIC ILLUSTRATION OF “CITRIC ACID TYPE” ASYMMETRY: THE MESO-CARBON ATOM
- Nuclear actin is associated with a specific subset of hnRNP A/B-type proteins
- A New Technique for the Production of A–b Translocations and Their Use in Genetic Analysis
- Simultaneous incorporation of magnesium and carbonate in apatite: effect on physico-chemical properties