The blue copper ligand field effect on the oxidized site. (A) shows the energy level diagram of an ideal tetrahedral structure which is orbitally degenerated and (B) shows the orbitally degenerated C3v structure; both have Jahn Teller distortion. (C) represents the Cs structure with no Jahn Teller distortion and D shows the splitting of the 3dxy level and 3dx2-y2 level by 10 000 cm-1