Kristallographisches und spektroskopisches Verhalten einiger gemischter Phosphat/Vanadat-Fluoroapatite

Abstract

Crystallographic data for mixed phosphate/vanadate fluoroapatites of the type M₁₀(P0₄)₆₋ₓ(V0₄)ₓF₂ (with M = Ca, Sr, Ba and x = 1-3) have been obtained from X-ray powder data. The only structural effect observed is a continuous increase of unit cell dimensions with increased vanadate incorporation. The IR and Raman spectra show that the V0₄³⁻ incorporation has a negligible effect on the strength of the P-O bonds, although a small bond weakening for both tetrahedral oxoanions is observed as the unit cell volum e increases. The results are comparable to those reported earlier for similar mixed hydroxyapatites and suggest that the fluoroapatite lattice can be considered as a good “model” for the vertebrate hard tissues.