The electronic configuration of V4+ implies a single CF transition 2T2g(2D) ! 2Eg(2D) in octahedral coordination,
that however is often split in three energy levels, owing to a dynamic Jahn-Teller effect occurring in low point symmetry sites, such as that of the srilankite structure [13,17,18]. On this basis, the transition y1 can be attributed to
2Ag ! 2B1g, 2B2g, as y2 can be assigned to 2Ag ! 2B3g (Fig. 4). These weak absorptions are responsible for the small
chroma differences among srilankite-type pigments: the stronger intensity of both peaks in AlV, for instance, justifies
the lack of any red cast, while the decreasing y1/y2 ratio accounts for the red and green contribution of InV and YV,
respectively.