title: Calcium phosphate clusters.
abstract: The potential energy surfaces associated with [Ca3(PO4)2n clusters are analyzed in detail using ab initio calculations for n ranging from one to four. Considering separated clusters, energy criteria favor the so-called Posner's cluster Ca9(PO4)6, which is the core of the actual structural model of amorphous calcium phosphate. This is rationalized through the existence of a distinct CaO bonding pattern in this cluster. Considering aggregated clusters as a possible model for amorphous calcium phosphate, the aggregation of Ca3(PO4)2 clusters appears as an alternative to Posner's hypothesis.
authors.affiliation: School of Science and Engineering Waseda University, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kanzaki
authors.forename: G
authors.initials: G
authors.lastname: Treboux
authors.forename: K
authors.initials: K
authors.lastname: Onuma
authors.forename: S
authors.initials: S
authors.lastname: Tsutsumi
authors.forename: A
authors.initials: A
authors.lastname: Ito
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D046911:Macromolecular Substances; D008422:Materials Testing; D008956:Models, Chemical; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D046911:Macromolecular Substances; C485828:alpha-tricalcium phosphate; C519480:amorphous calcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous