Study of local structures and optical spectra for octahedral Fe3+ centers in a series of garnet crystals A3B2C3O12 (AÂ =Â Cd, Ca; BÂ =Â Al, Ga, Sc, In; CÂ =Â Ge, Si)

Being independent of the sign of parameter b20 , it is close gradually to zero point along with parameter R increasing.