The catalytic effect of impurity. The effect of benzene, acetone, organic acids, iron, and chromium on growth of KH2PO4 and C8H5O4K crystals

The effect of benzene, acetone, acetic, formic, and oxalic acids, iron, and chromium on the growth kinetics of KH2PO4 and C8H5O4K crystal faces has be en studied. It is found that low concentrations of organic impurities incre ase growth rates of some crystal faces (the so-called catalytic effect of i mpurity). This effect is rather weak in the case of organic acids, however, it is clearly seen in the presence of inorganic impurity (Fe3+). The analy sis of two models of growth (dislocation-free and B + S) under the assumpti on that the main cause of the catalytic effect is a decrease in the step en ergy showed that the calculated and experimental data are consistent only u nder certain assumptions that should be additionally verified both theoreti cally and experimentally. (C) 2000 MAIK "Nauka/Interperiodica".