Titre du document / Document title

A misunderstood member of the nagelschmidtite family unveiled: structure of Ca₅Na₂(PO₄)₄ from X-ray powder diffraction data

Auteur(s) / Author(s)

CELOTTI G. ⁽¹⁾ ; LANDI E. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ IRTEC-CNR, via Granarolo, 64, 48018 Faenza, ITALIE

Résumé / Abstract

During the development of procedures to synthesize carbonate hydroxyapatite with properties resembling those of biological material, a new phase was found to form after high temperature treatments in the presence of sodium. The compound was isolated and analytically characterized, leading to its identification as Ca₅Na₂(PO₄)₄: an analogous Ca-Na phosphate was previously described, but with rather poor diffraction data and uncertain stoichiometry. Accurate XRD powder patterns revealed a hexagonal cell, space group P6₃mc (186), a = 10.64 Å, c = 21.71 Å, Z = 6, ρ = 2.93 g/cm³, with the a axis double and the c axis triple those of the subcell typical of α-phases in the well-known system A₂XO₄ (or ABXO₄). The complete structural determination was carried out and the relevant aspects and properties discussed.

Revue / Journal Title

Journal of the European Ceramic Society   ISSN 0955-2219 

Source / Source

2003, vol. 23, n^o6, pp. 851-858 [8 page(s) (article)] (25 ref.)

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Oxford, ROYAUME-UNI  (1989) (Revue)

Mots-clés anglais / English Keywords

Inorganic compound ; Non stoichiometric composition ; Crystalline structure ; X ray diffraction ; Sodium phosphate ; Calcium phosphate ; Chemical preparation ; Experimental study ;

Mots-clés français / French Keywords

Composé minéral ; Ca Na O P ; Ca5Na2(PO4)4 ; Composition non stoechiométrique ; Structure cristalline ; Diffraction RX ; Sodium phosphate ; Calcium phosphate ; Préparation chimique ; Etude expérimentale ;

Mots-clés espagnols / Spanish Keywords

Compuesto inorgánico ; Composición no estequiométrica ; Estructura cristalina ; Difracción RX ; Calcio fosfato ; Estudio experimental ;

Localisation / Location

INIST-CNRS, Cote INIST : 21153, 35400010751080.0050