The fine structure of the dielectric function in the spectral range 0.5-5.0
eV was studied in the [M2Cu2O3](m) [CuO2](n)-type crystals (where M = Ca,
Sr, Y, Bi, rare earth elements) with the min values equal to 1/1,5/7, 7/10
and 9/13. The spectra were compared with those of structural analogues CuO,
SrCuO2, Ca2CuO3 and LiCu3O3, containing similar Cu-structural units as wel
l as with the spectra of other complex cuprates such as Y-123 and Bi-2212.
The qualitative analysis of the spectra allowed one to reveal the correlati
on between optical features in the spectra of [M2Cu2O3](m) [CuO2](n), cryst
als and electronic excitations in corresponding structural units. On the ba
sis of the correlation, the microstructure of various [M2Cu2O3](m)[CuO2](n)
crystals was discussed. The general regularities in the fine structure of
complex cuprates were described and the specific features for [M2Cu2O3](m)[
CuO2](n), crystals were emphasized.