[en] Effective electron radii in liquid homogeneous mixtures of alkali metals and their halides are evaluated within the framework of rigid-sphere approximation, halide melt complex structure model and respective state theory. It is shown that application of the respective state theory based on the search and introduction of dimensionless parameters (criteria) of similaring for the description of liquids with different character of interparticle x linkings and taking account of their complex structure, can be useful when evaluating the density of particle packing and other properties of ion-electron metls, linked with the molar volume