The crystal structure of α-Ca3(PO4)2

Abstract

ct-Ca3(PO4) 2 crystallizes in the monoclinic space group P2Ja with a= 12.887(2), b=27.280(4), c--15.219 (2) ,~,/~ = 126.20(1) °, and Z = 24. An approximate subcell with b' = b/3 exists. The structure was solved by direct methods of phase determination and refined to R = 0.051 and R,= 0.049 with 7002 reflections collected from a single crystal by counter methods. The structure consists of columns of cations, and columns of cations and anions with compensating cation vacancies, and is closely related to the structure of K3Na(SO4) 2, the mineral glaserite. The calcium ions in ct-Caa(PO4) 2 exhibit a wide range of coordination numbers and geometries.

An evaluation of methods to determine the porosity of calcium phosphate cements

“…Samples for porosity measurements were treated similar to the acidic CPC samples. For Rietveld analysis from XRD measurements, the additional PDF files used was taken from PDF #01-074-0565 (HA), 26 PDF #04-010-4348 (a-TCP), 27 and PDF #04-008-0788 (calcite). 28 Furthermore, the densities used for theoretical density calculations were, in addition to the ones used for the acidic CPCs also, HA 3.16 g/cm 3 , and calcite 2.71 g/cm 3 .…”

Distrontium nickel orthophosphate

“…Single-crystal X-ray analyses of orthophosphates M3(PO4)2, where M is an alkaline-earth or bivalent transition metal, have been reported for ol-Ca3(PO4)2 (Mathew, Schroeder, Dickens & Brown, 1977),/3-Ca3-(PO4)2 (Dickens, Schroeder & Brown, 1974), Ca3(PO4)2 (high pressure; Roux, Loiier& Bonel, 1978), ot-Sr3(PO4)2 and Ba3(PO4)2 (Zachariasen, 1948), Co3(PO4)2 (Anderson, Kostiner, Miller & Rea, 1975), Ni3(PO4)2 (Calvo & Fagiani, 1975), Cu3(PO4)2 (Shoemaker, Anderson & Kostiner, 1977), ol-Zn3(PO4) 2 (Calvo, 1965), /3-Zn3(PO4)2 (Stephens & Calvo, 1967), Fe3(PO4)2 (Kostiner & Rea, 1974), Mg3(PO4)2 (Nord & Kierkegaard, 1968) and /3t-Mn3(PO4)2 (Stephens & Calvo, 1969).…”

Hydroxyapatite-Forming Ability and Mechanical Properties of Organic-Inorganic Hybrids Reinforced by Calcium Phosphates

“…The density of a-TCP is 2.86 gcm 3 . 24 The porosities of TCP-SP and TCP-BP were calculated from their weight and volume by using the density of the HEMA-MPS hybrid and the porosity of TCP-PB. The porosity of CPP-SP was calculated from its weight and volume by assuming that the mass ratio of HEMA-MPS hybrid : powder is 3 : 7.…”