Mutual interaction of redox pairs in silicate melts: V5+/V4+/V3+/V2+ tetrad and other equilibria

Mutual interaction of redox pairs was evaluated using the concept of intrinsic oxygen fugacity in a melt. A “rose of $f_{O_2 } $ trends” was proposed for the visualization of possible directions of mutual oxidation/reduction of redox pairs for a given melt composition. Missing thermodynamic data were estimated for vanadium redox pairs in sodium disilicate melt, and the V⁵⁺/V⁴⁺/V³⁺/V²⁺ tetrad was quantitatively described. The redistribution of vanadium in different valence states was estimated during quenching to glass of model iron-free and natural iron-bearing melts.