Fluorapatite (Ca5F(PO4)3)

Description

This apatite is formed by the same methods as the calcium apatite analog. The solid-state reaction required is:
6SrHPO4 + 3SrCO3 + SrF2 + heat?Sr10F2(PO4)6 + 3CO2 + 3H2O
It has also been prepared by the solution method:
10SrF2 (aq) + 6Na3PO4 (aq)?Sr10(F)2(PO4)6 (solid) + 18NaF (aq) + 2HCl
However, the product is contaminated by Na⁺ ions and must be washed thoroughly to obtain a pure product. A small amount of hydroxyapatite may also be present.
Strontium fluorapatite has been shown to be one of the best hosts for Nd³⁺ doping among apatite crystals. Neodymium-doped strontium fluorapatite crystal has been grown by the Czochralski method. The data of thermal expansion and specific heat of the crystal have been measured. The thermal expansion coefficients along X and Z direction are a1 =11.4×10^-6/K and a3 = 12.3×10^-6/K, respectively. The specific heat is 110 cal/mol K at 330 K. The measured absorption spectra from 400 to 850 nm showed that the crystal has absorption peaks around 805.5 nm, and the absorption coefficients at 805.5 nm are 16.05/cm and 5.59/cm for p and a-polarization, respectively.
Strontium fluoroapatite does not have a CAS number even though it is still used as a phosphor for compact and standard fluorescent lamps. It has been the subject of numerous academic studies but has found little or no usage in industry except those already mentioned.

Chemical properties

fluoroapatite is a mineral for fluorine; can be prepared from CaCl2 and sodium monofluorophosphate; used as a laser crystal(s), may have the lowest energy threshold of any crystal(s) at room temp [KIR78] [HAW93]

The Uses of Fluorapatite (Ca5F(PO4)3)

Apatite is one of a few minerals produced and used by biological micro-environmental systems. The primary use of apatite is in the manufacture of fertilizer, it is a source of phosphorus. It is occasionally used as a gemstone. Green and blue varieties in finely divided form, are pigments with excellent covering power.