Chemical Properties
white powder
Uses
Prosthetic aid (artificial bone and teeth).
Brand name
Alveograf (Sterling Winthrop); Periograf (Sterling Winthrop).
Description
Calcium hydroxyapatite has a unique structure in
that it is conductive along the hydroxide channels.
OH- ions lie at (1/4/,1/4,1/4) and (3/4/,3/4,3/4) on
the c-axis and charge-carrying protons are responsible
for the observed conductivities in M10(PO4)6(OH)2. The
H+ migration between the electroattractive ion (O2)
to give molecular H2O in matrix channels carries charge
and the resulting conductivity.
The unit cell consists of two triangular prismatic subcells
forming a rhombic prism with vertical sides. There
are two horizontal mirror planes at the OH levels of 1/4
and 3/4 of the c-axis. In addition, there is a center of
inversion exactly in the center of each vertical face of
each subcell.
Occurrence
Occurs in nature as the minerals: oxydapatit, voelicherite, whitlockite.
Preparation
The technical product is also known as “bone ash.” Commercial preparation from phosphate rock.
General Description
Bone and tooth implant materials have been prepared from polycrystalline hydroxyapatite. The compressive, flexural, torsional and dynamic torsional strengths of polycrystalline hydroxyapatite were investigated. Electrophoretic deposition of hydroxyapatite on to flat titanium plate material has been studied.
Flammability and Explosibility
Notclassified
Pharmaceutical Applications
Modified hydroxylapatite, also frequently called hydroxyapatite and better known as bone mineral, makes
up ～50% of our bones. Hydroxylapatite is a natural form of the mineral calcium apatite, whose formula is usually denoted as Ca10(PO4)6(OH)2. Modifications of hydroxylapatite can also be found in the teeth, and a
chemically identical substance is often used as filler for replacement of bones, and so on. Nevertheless, despite
similar or identical chemical compositions, the response of the body to these compounds can be quite different.
