Crystals of cubic zinc sulfide with different isotopic compositions have been grown by iodine vapor transport for basic research purposes (vibrational electronic and thermodynamic properties) The synthesis reaction in sulfur vapor was found to be controlled by solid-state diffusion of zinc atoms through a ZnS passivation layer Crystals up to 5 mm in length were grown from small amounts of source material The presence of argon reduced the nucleation density and favored the formation of facets An one-dimensional stoichiometric transport model including iodine dissociation and considering multi-component diffusion results in an explicit formula of the transport rate in terms of the Peclet number The derivation of an iodine-based Peclet number allows correlation of the iodine concentration gradient with the usual inert gas based expression and simplifies the present calculation of the partial pressures The transport rate the Peclet number and also the growth-relevant diffusion coefficient are given as functions of the iodine concentration and the inert gas pressure The experimental results depicted in a linear diagram are in reasonable accordance with the theory except for single cases that can be explained possibly by foreign vapors and zinc excess respectively (C) 2010 Elsevier B V All rights reserved