GROWTH OF CHLORAPATITE CRYSTALS FROM A SODIUM-CHLORIDE FLUX

Well-formed crystals of chlorapatite [Ca5Cl(PO4)(3)] were first grown from a sodium chloride flux. The solubility of Ca5Cl(PO4)(3) in NaCl i ncreased with increasing temperature. At 1100 degrees C, Ca5Cl(PO4)(3) had a solubility of about 0.15 mol%. The crystal growth of Ca5Cl(PO4) (3) was conducted by heating a mixture of solute and flux at 1100 degr ees C for 10 h, followed by cooling to 500 degrees C at a rate of 5 de grees Ch(-1). Colorless and transparent crystals having lengths up to 4.0 mm and widths of 1.2 mm were grown from high-temperature solutions containing small amounts of solute (0.05-0.5 mol%). The obtained crys tals were divided into two distinct morphological types: prisms and ne edles. The most suitable solute contents for the growth of prismatic a nd needle crystals were 0.15 and 0.1 mol%, respectively. The crystal f orms were also dependent on the solute content. The prismatic crystals were bounded by the {10 (1) over bar 0} and {10 (1) over bar 1} faces . The needle crystals elongated in the (0001) directions. Calcium, chl orine, phosphorus, and oxygen were almost homogeneously distributed in the crystals.