Dicalcium Phosphate

Last time importance of the efficient and resource-saving technologies for synthesis and applications of new inorganic polymers-condensed phosphates are out of any doubt which explains the relevance of our works thanks to our technological methods and experience that we have cultivated over many years. Presented work review information about synthesized by us many crystals and/or powder of diverse new groups of condensed phosphates, during investigations of the systems M I 2 O-M III 2 O 3-P 2 O 5-H 2 O at 400K-850K (where M I are various monovalent metals, M III-diverse trivalent metals). Numerous new formerly unknown double condensed phosphates have been obtained and t he possibilities of their application are investigated. Synthesized by us cyclic octaphosphate K 2Ga2P8O24 was studied for the catalytic activity and the results showed that it has unique properties as an inorganic polymer and can be used as a best catalyst during organic synthesis reactions for the preparation of low molecular weight dienic olefines.

Amorphous calcium phosphates (ACPs) represent a metastable amorphous state of other calcium orthophosphates (abbreviated as CaPO 4) possessing variable compositional but rather identical glass-like physical properties, in which there are neither translational nor orientational long-range orders of the atomic positions. In nature, ACPs of a biological origin are found in the calcified tissues of mammals, some parts of primitive organisms, as well as in the mammalian milk. Manmade ACPs can be synthesized in a laboratory by various methods including wet-chemical precipitation, in which they are the first solid phases, precipitated after a rapid mixing of aqueous solutions containing dissolved ions of Ca 2+ and PO 4 3− in sufficient amounts. Due to the amorphous nature, all types of synthetic ACPs appear to be thermodynamically unstable and, unless stored in dry conditions or doped by stabilizers, they tend to transform spontaneously to crystalline CaPO 4 , mainly to ones with an apatitic structure. This intrinsic metastability of the ACPs is of a great biological relevance. In particular, the initiating role that metastable ACPs play in matrix vesicle biomineralization raises their importance from a mere laboratory curiosity to that of a reasonable key intermediate in skeletal calcifications. In addition, synthetic ACPs appear to be very promising biomaterials both for manufacturing artificial bone grafts and for dental applications. In this review, the current knowledge on the occurrence, structural design, chemical composition, preparation, properties, and biomedical applications of the synthetic ACPs have been summarized.

Amorphous calcium phosphates (ACPs) represent a metastable amorphous state of other calcium orthophosphates (abbreviated as CaPO4) possessing variable compositional but rather identical glass-like physical properties, in which there are neither...