The chemical vapor transport and crystal growth properties of the Hgl−xCdxTe iodine system (x=0.2, 0.5 and 0.7) are investigated as a function of transport agent pressure and orientation of the density gradient with respect to the gravity vector to understand the effects of convection on mass transfer and crystal morphology. A thermodynamic analysis of the solid-gas phase system yielded the composition of the vapor and the partial pressures of the gaseous species as a function of temperature and total pressure to assist in the elucidation of the dominant transport mode. Optical and scanning electron microscopy, electron microprobe, chemical etching, X-ray diffraction and energy dispersive spectroscopy techniques were employed to examine the surface and bulk morphology and compositional homogeneity of single crystals obtained under different conditions.