ON THE NATURE OF MANGANESE IONS IN THE BETA-CA2SIO4 STRUCTURE DETECTED BY HIGH-FIELD ESR

The stabilization effect of dopants of the structure of beta-dicalcium silicate using manganese in different oxidation states was investigated in detail by ESR at 3.2 cm (X-band), 8 mm (Q-band) and by high field ESR at 2 mm (W-band). The assignment of the signals was supported by corresponding single crystal measurements using X-Band and Q-band. If there are only low manganese concentrations on forming the microcrystallites the incorporated Mn2+ will be localized on less distorted sites of the lattice. Increasing the manganese concentration the Mn2+ spectra are superimposed by the fine structure of Mn2+ and of Mn4+ ions occupying distorted lattice sites with axial and rhombic symmetry. This pattern of the cation substitution represents the typical transition metal behaviour and obviously favours the formation of regular crystalline units from the melt on compensating of nonequivalent distances and charges.