Hydrated sites in biogenic amorphous calcium phosphates: An infrared, raman, and inelastic neutron scattering study
Mitchell, P.C.H.; Parker, S.F.; Simkiss, K.; Simmons, J.; Taylor, M., G.
Journal of Inorganic Biochemistry 62(3): 183-197
Amorphous minerals are widely distributed in biology, and occur as carbonates, phosphates, and silica. Calcium and magnesium are the major cations in the phosphate deposits, but in addition, there is usually an organic component, and the minerals are hydrated with up to 20% water. Such deposits are found as intracellular granules in a variety of invertebrates such as the shore crab Carcinus maenas. These intracellular granules and synthetic amorphous calcium phosphates and crystalline apatite have been studied by infrared, Raman, and inelastic neutron scattering to establish the protonation of the phosphates and the structure of the water in these deposits. Monetite and newberyite were used as model compounds for comparison. It is concluded that the water occurs in regions that are only loosely associated with the cations in these solids.