Crystallography of tetracalcium phosphate

Abstract

Te tracalcium phos phate, Ca.O(p04j" has a monoclinic modifi cation with the paramete rs a= 11.99, b = 9.48 , a nd c= 6.97 A , a =90.8°, z= 4 , and space group P2, or P2dm. From a co mpa ri son with tbe wo rk of Trom e l a nd Zaminer , it is co nc luded th at thi s s alt has monoclini c a nd orthorho mbi c modifi· ca ti ons with th e mos t probable s pace groups be in g P2, and P2,22" respec tiv e ly.Th e res ult s s upport th e view th a t t etracalc ium ph os phate has a layer-t ype structura l re lati ons hip to h yd rox ya patite, Ca5(OH)(P04), . This wou ld acco unt, in pa rt , for variation s in th e co mpos iti ons of a patitic materi als in which the rati o Ca/p is grea te r th an 10/6, a nd it s ugges ts that tetraca lc ium phos phate may be prese nt in th e min e ra l of tooth a nd bon e.Key Words : Hilge ns toc kit e, tetraca lc ium phos phat e , h ydroxyapa tit e, bone min e ral, too th min e ra l, unit ce ll , sym me try. twinnin g.

Effect of Gamma Radiation on Properties of a Calcium Phosphate-Calcium Sulfate Composite Cement

“…20) Appropriate amounts of in-house prepared TTCP and commercial DCPA powders were uniformly mixed, followed by mixing with an appropriate amount of CSH powder. The resultant TTCP/ DCPA/CSH powder mixture was £-ray-sterilized at China Biotech Co. (Taichung, Taiwan) with a series of different £-ray doses (25,50, 75 and 100 kGy) for the study.…”

Synthesis, Properties and Hydration Characteristics of Novel Nano-Size Mineral Trioxide and Tetracalcium Phosphate for Dental Applications

“…TTCP is the only calcium phosphate phase with a Ca/P ratio greater than stoichiometric hydroxyapatite (HA), and is formed above 1300 o C in CaO-P 2 O 5 system. At a temperature range 1000-1200 o C the compound is metastable, therefore the synthesis of the TTCP phase-pure requires either rapid quenching or the absence of moisture to prevent decomposition to HA 14,15 .…”

Investigation of Changes in Phases and Properties of a TTCP/DCPA/CSH Cement Immersed in Hanks’ Solution

“…16) Appropriate amounts of in-house prepared TTCP and commercial DCPA powders were uniformly mixed, followed by mixing with an appropriate amount of CSH powder. The resultant TTCP/ DCPA/CSH powder mixture with a weight ratio of 0:89 : 0:33 : 1 for each constituent (or a weight ratio of 55 : 45 for TTCP/DCPA: CSH) was mixed uniformly with a 0.6 M (NH 4 ) 2 HPO 4 setting solution at a liquid/powder (L/P) ratio of 0.35 cc/g to form a cement.…”