Chrysotile asbestos fibres from Quebec: electron magnetic resonance identification

Quebec chrysotile asbestos fibres have been examined by EPR spectroscopy at room T and 77 K. Finely divided samples show an absorption due to manganese(II) at g = 2.0with a hyperfine coupling of 90 gauss. Several types of ferric ions are present in addition to magnetite. These include surface adsorbed hydroxides and lattice bound ions. From the EPR spectrum of structurally bound iron in long fibres oriented perpendicularly to the magnetic field, it was found that the ferric ions are in a rhombic environment. EPR thus shows promise as a tool for the identification and characterization of asbestos fibres.