Investigation of iron sulfides by γ-resonance Mössbauer spectroscopy

1. Nine minerals of iron, belonging to the class of complex iron sulfides, were studied by the method of γ resonance spectroscopy. 2. The data obtained indicate that in sphalerite, wurtzite, pentlandite, cubanite, stannite, and berthierite, iron exists in the Fe²⁺ state, while in chalcopyrites and bornite it exists in the Fe³⁺ state. 3. In similar structures, the value of the isomeric shift depends upon the coordination and valence state of the iron atom, so that δ[Fe²⁺(6)] > δ[Fe²⁺(4)] > δ[Fe³⁺(6)] > δ[Fe³⁺(4)]. 4. The nature of the Fe-S bond depends upon the structure of the second coordination sphere, and the ionic nature of the bond is the greatest in those cases when the sulfur atom is also bonded to the Sn⁴⁺ and Sb³⁺ atoms, which strongly attract the electron cloud of the sulfur ion. 5. The presence of a local magnetic field was detected in magnetically ordered systems.