Crystallochemical and Voltammetric Characterization of the Zn2 – 2хMn2хSiO4 Luminophor

Resumo

The region of homogeneity in a solid solution of the nominal composition Zn_2 – 2xMn_2xSiO₄ (х ≤ 0.21 ± 0.01) is determined. A comparison of the values of the pycnometric and X-ray densities for the compositions with x ≥ 0.13 ± 0.01 indicates the coexistence of manganese ions in two charge states: Mn²⁺ and Mn³⁺. It is established voltammetrically that all of the manganese ions in Zn_1.8Mn_0.2SiO₄ are divalent, and the concentrations of Mn²⁺ and Mn³⁺ ions in Zn_1.6Mn_0.4SiO₄ are comparable. The oxidation of some Mn²⁺ ions results in the concentration quenching of luminescence in Zn_2 – 2xMn_2xSiO₄ solid solutions at х > 0.13 ± 0.01.