- The influence of γ-radiation on solid iron compounds could be studied in a non-destructive manner by the use of Mössbauer spectroscopy /11/; it is found e.g. that in hexaquo-iron(II) compounds one water molecule on average is radiolysed to H and OH in a primary step, the coordinated OH radical then reducing iron(II) to iron(III). Aqua complexes of iron(III), however, do not undergo the subsequent redox process, because iron(III) is more stable than iron(IV).
- Ligand substitution reactions with iron compounds could also be convincingly studied by Mössbauer spectroscopy. Starting with a mixture of FeSO4.7H2O/KCN (1:6) one could observe a rapid substitution of five coordinated water molecules by five cyanide ligands converting the original high spin compound into a low spin species, but the 6th water molecules is replaced slowly by cyanide to the hexacyano complex /13, 30/.
- The chemical alteration of the iron containing Fischer-Tropsch catalyst during the actual hydrocarbon production was followed by Mössbauer spectroscopy /111/.
- Clays and minerals were characterized spectroscopically; the Mössbauer technique allowed to identify the various oxides and hydroxides, generated in different soil samples, by virtue of their different magnetic behaviour /79, 90, 184/. The presence of aluminium in alumogoethites changes significantly the local magnetic field. As the magnitude of the local magnetic field turned out to depend on the aluminium concentration, one could use this effect to develop a method of aluminium determination in such minerals which are of importance for the aluminium production /51/.
- Mössbauer spectroscopy has also proven to be powerful technique for the quality control of magnetic audio and video tapes based on CrO2 pigments doped with up to 5 % iron. It was found that iron enters the lattice in two ways, as mixed crystals Fe2O3/Cr2O3 which deteriorates the magnetic properties, and substitutionally replacing the Cr in the CrO2 lattice which improves the magnetic properties. In a collaboration with BASF company our studies have led to an improvement of the magnetic properties of the pigments by ca. 10% /187, 199, 262/.