Premium
Manganese in Precipitated Hydroxyapatites
Author(s) -
Mayer Isaac,
Jacobsohn Orit,
Niazov Tamara,
Werckmann Jacques,
Iliescu Monica,
RichardPlouet Mireille,
Burghaus Olaf,
Reinen Dirk
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200390188
Subject(s) - chemistry , carbonate , manganese , hydroxyapatites , apatite , impurity , precipitation , aqueous solution , infrared spectroscopy , inorganic chemistry , nuclear chemistry , mineralogy , analytical chemistry (journal) , calcium , physics , organic chemistry , chromatography , meteorology
Abstract The synthesis of Mn‐containing hydroxyapatite (HA) samples was carried out by precipitation from an aqueous solution with and without carbonate at pH 5.8−6.0. Chemical analyses have shown that Mn uptake (about 70%) is proportional to the amount of initially added Mn. The molar Ca/P ratios of the samples (1.53−1.63) indicate the formation of nonstoichiometric HA, with the higher values being obtained for the carbonated samples. Powder X‐ray diffraction (XRD) and IR spectroscopy have shown well‐defined patterns with structural data characteristic of HA. The calculated lattice constants were found to be similar to those known for HA, without any effect of the varying Mn content. High temperature treatment of selected samples was studied by XRD and IR and showed that the apatite structure is stable up to 400 °C for all samples. At 600 °C samples with low carbonate content transform partially, and at 800 °C completely, to β‐Ca 3 (PO 4 ) 2 , while for samples with higher carbonate content (3.5−6.0%) the apatite structure is stable up to 800 °C, and a colour change to blue occurs. EPR spectroscopy reveals that manganese is divalent in all precipitated samples and present in a cubic impurity phase. After heating above 600 °C it is partially oxidized to Mn V in the samples with high carbonate content and enters the HA lattice as the blue MnO 4 3− ion. In the carbonate‐poor solids Mn 2+ seems to partly occupy the Ca 2+ sites in β‐Ca 3 (PO 4 ) 2 when sintered at temperatures above 400 °C. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)