ABSTRACT
Investigation of the structural roles of carbonate and hydroxyl
ions and water molecules in biological apatites has leaned heavily
on techniques of chemical spectroscopy. Although it has been
appreciated for some time that the inorganic component of bone
is similar to hydroxylapatite,6,144 the physical state and chemical
reactivity of biological apatite crystals has frustrated all attempts
to obtain detailed structural information using conventional powder
diffraction methods. Crystals of biological apatites are nanoscale in
size, have poor crystallinity, and contain low amounts of carbonate.
Synthetic analoguematerials precipitated from aqueous solution are
similarly limited. In addition, bone mineral crystals are too fragile
chemically to separate from the organic matrix in the pristine state
for single-crystal diffraction studies. Fourier transform infrared
spectroscopy (FTIR) has proven to be the most useful molecular
spectroscopy technique for studying analogue and biological apatite
materials, and its application will be emphasized in this chapter.
Nuclearmagnetic resonance spectroscopy allows unique insight into
the chemical state and structural role of channel species, in particu-
lar, and the results from these studies will be briefly reviewed also.
