, and (iii) A 2 (F)→ 4 T 1 (P), whereby only the latter one falls in the visible region centered at about 2 eV. Further evidence is given by the HSE06 partial DOS for cubic LLZO Co 2+ in tetrahedral coordination as shown in Figure (cf Figure ). Here, Co 2+ introduces occupied cobalt states above oxygen states and unoccupied cobalt states in the energy gap with similar appearance compared to the absorption spectrum. Tetrahedral coordination of Co 3+ is unfavorable coordination environment but has been observed previously for mixed-valent Codoped YAG and YGG. Those garnets have shown a greenish color may be associated with the absorption in the blue (Co 3+ on Td) and red region (Co 2+ on Td) as obvious by combining the spectra of LLZO-b and LLZO-o. The bands associated with Co 3+ on the tetrahedral side can be potentially assigned to a 5 E→ 5 T 2 transition. Further evidence for the assignment is again given by the partial DOS as obtained for LLZO with Co 3+ located on the tetrahedral side having Co 3+ unoccupied states present in the energy gap with similar appearance compared to the absorption spectrum explaining the observed orange color change.