Absorption spectra of calcium tartaric and cadmium oxalate crystals, grownin gel and doped by chromium, cobalt and nickel

This article is devoted to the insertion of admixture atoms to crystals dur ing growth in gel and their influence on the optical properties of the obta ined crystals. The crystals of tetra-hydrate calcium tartaric (CaC4H4O6.4H( 2)O) and trihydrate cadmium oxalate (CdC2O4.3 H2O) [1, 2] were grown in sil ica-gel and doped during this process by chromium, cobalt and nickel atoms. This procedure causes changes of the optical properties of the crystals, i n particular changes of the color. The extinction of the obtained crystals measured by us provides a quantitative description of this evolution.