Organic radicals in natural apatites according to EPR data: Potential genetic and paleoclimatic indicators

In a group of natural marine apatites Ca₅(PO₄)₃(F, OH), organic ?H₃, ?H₂—R, HO?HR, (CH₃)₂—?R, and —?_org radicals are identified by EPR. The relation between the EPR spectra of the observed organic radicals, the valence form, and the structural location of impurity vanadium ions (V⁴⁺ (VO²⁺) on the Ca²⁺ II site or V⁵⁺ (VO₄)^3- → (PO₄)^3-) is established. The structure of organic radicals correlates with the type of organic matter in the sample under analysis: sapropelic or humic, depending on the climatic conditions of mineral genesis.