Isolation and Characterization of a Characteristic Phosphato-Silicate from Human Lungs with Silicosis

Summary

In studies on the inorganic components of human lungs with silicosis (181 lungs) a unique compound was found, present in 180 lungs, but absent in controls without silicosis (67 lungs). About 0.22 g of this compound have been isolated from 4 lungs and chemically and structurally analyzed. Its composition and structural formula is given by

$$ {{\rm{M}}^{\rm{ + }}}_{{\rm{1}}{\rm{.45}}}\,{\rm{(}}{{\rm{H}}_{\rm{2}}}{\rm{O)}}\,{\rm{ \times }}\,{\rm{\{ Fe}}_{{\rm{0}}{\rm{.90}}}^{{\rm{ + 3}}}\,{\rm{Fe}}_{{\rm{1}}{\rm{.10}}}^{{\rm{ + 2}}}\,{\rm{(OH)}}\,{\rm{S}}{{\rm{i}}_{{\rm{3}}{\rm{.36}}}}\,{{\rm{P}}_{{\rm{0}}{\rm{.64}}}}\,{{\rm{O}}_{{\rm{11}}}}{\rm{\} }} $$

The cations M⁺ are exchangeable, the water molecules can be replaced by many polar organic compounds. The anion has a double-chain structure with accessible internal surfaces of high catalytic activity. The replacement of silicon by phosphorous is unusual in silicates.