Physico-chemical aspects of calcium vanadate apatite

Abstract

By appropriate modifications of existing precipitation methods, a sample of calcium vanadate apatite, Cal0(VO4)e(OH)2 was prepared at 11 0 ° C. It was characterized through X-ray, electron microscopic, infrared and thermoanalytical analyses in addition to chemical analysis. Equilibrating the sample in buffered aqueous media at 37 ° C, the solubility was measured using microanalytical techniques of Ca 2+ and VO 3-present in the saturated solutions after separating the colloidal component of the solute. Duration of equilibration for the attainment of saturation of the solution of the sample was obtained from a study on its dissolution kinetics. The pK~p of calcium vanadate apatite was found to be 1 07.09. The investigation showed that pK~p was independent of the presence of the common ions.

Synthesis and Investigation of Physicochemical Properties and Biocompatibility of Phosphate–Vanadate Hydroxyapatite Co-Doped with Tb3+ and Sr2+ Ions

“…In all recorded ATR-FT-IR spectra ( Figure 4 a–c), bands originating from the phosphate (PO 4 3− ), vanadate (VO 4 3− ) and hydroxyl (OH − ) groups are present. Their locations are consistent with the data available in the literature and confirm that the materials have the hexagonal structure of phosphate–vanadate hydroxyapatite [ 17 , 19 , 48 , 57 , 58 ].…”

“…It can result in obtaining unique acid–base catalysts and highly active oxidation catalysts due to the Lewis acidic properties and appropriate redox potential of vanadium [ 17 ]. Due to the structural similarity of vanadate to phosphate, it can take over a regulatory function in cellular processes in which phosphate plays a key role [ 18 , 19 ]. This phenomenon is based on vanadate’s interaction with phosphate-dependent enzymes, i.e., phosphatases and kinases [ 20 ].…”

Reduction by hydrogen of vanadium in vanadate apatite solid solutions

“…4,6 Various studies of complete or partial isomorphous substitution of PO 4 3À by AsO 4 3À or VO 4 3À in the lattice of hydroxyapatite have been published. [7][8][9][10][11][12][13] Recently, we reported studies by UV, XRD, XPS, NMR and FTIR on the influence of the substitution degree x, on the local structure of the vanadate group in calcium phosphate and vanadate apatite solid solutions, Ca 10 (PO 4 ) 6Àx (VO 4 ) x (OH) 2 . 14 It was shown that the vanadate ions occupy the equivalent crystallographic sites of phosphate and that the presence of both phosphate and vanadate ions in the lattice led to high disorder of the structure accompanied with small changes in local symmetry.…”

Effects of vanadium (V) and magnesium (Mg) on rat bone tissue: mineral status and micromorphology. Consequences of V–Mg interactions

“…Mravcova ´et al 15 found that epiphyseal cartilage and the subperiosteous zone of the diaphysis accumulate V and that deposition of this metal is greatest in areas of recent bone formation and mineralization. It has also been reported that vanadate (VO 4 3À ) is incorporated into the HA lattice [Ca 10 (PO 4 ) 6 (OH) 2 ] replacing phosphate anions (PO 4 3À ) 10,81 and forming calcium vanadate apatite [Ca 10 (VO 4 ) 6 (OH) 2 ], 82 whereas, oxidovanadium(IV) (VO 2+ ) [vanadyl] is strongly adsorbed on the apatite lattice surface. 8 The incorporation of small quantities of VO 4 3À in the PO 4 3À sites has been highlighted to produce only slight distortions in the macroscopic and microscopic structure of the mineral phase of bones.…”