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Phase Relations Between β‐Tricalcium Phosphate and Hydroxyapatite with Manganese( II ): Structural and Spectroscopic Properties
Author(s) -
Mayer Isaac,
Cuisinier Frederic J. G.,
Popov Ina,
Schleich Yechezkel,
Gdalya Sarit,
Burghaus Olaf,
Reinen Dirk
Publication year - 2006
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.200501009
Subject(s) - chemistry , manganese , electron paramagnetic resonance , spectroscopy , phase (matter) , crystallography , divalent , calcium , nuclear magnetic resonance , organic chemistry , physics , quantum mechanics
The preparation of Mn‐containing β‐tricalcium phosphate (β‐TCP) samples was achieved in two ways: a) transformation of precipitated Mn‐containing calcium hydroxyapatite (HA) to β‐TCP by heating at 1100 °C, and b) preparation by solid‐state reaction of a mixture of CaCO 3 , (NH 4 ) 2 HPO 4 , and Mn(NO 3 ) 2 at 1100 °C. Powder X‐ray diffraction (XRD) analyses of the samples, obtained by both methods, show well‐defined patterns with structural data of the rhombohedral R3c, β‐TCP phase. The calculated lattice constants are smaller than those known for β‐Ca 3 (PO 4 ) 2 because of substitution of Ca 2+ by Mn 2+ . EPR spectroscopy indeed reveals that manganese is divalent in the samples. Apparently, the Ca(5) site in the β‐TCP structure is occupied by Mn 2+ . The distribution of Mn 2+ between the β‐TCP and the HA phase in the case of preparation (b) was studied by EPR spectroscopy, and a pronounced preference for the former lattice was found. Micron‐ and submicron‐sized crystals with visible faces were observed by TEM in the case of β‐TCP prepared by solid‐state reaction, and large micron‐sized, droplike‐shaped crystals, sensitive to beam radiation, were found in the case of samples prepared by heating HA at elevated temperatures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)