The effects of thermo-solutal convection on mercurous chloride system of Hg2Cl2 and Ne during physical vapor transport are numerically investigated for further understanding and insight into essence of transport phenomena. For 10 K ≤ΔT ≤ 30 K, the growth rate slowly increases and, then is decreased gradually until ΔT = 50 K. The occurrence of this critical point near at ΔT = 30 K is likely to be due to the effects of thermo-physical properties stronger than the temperature gradient corresponding to driving force for thermal convection. For the range of 10 Torr ≤ PB≤ 300 Torr, the rate is second order-exponentially decayed with partial pressures of component B, PB. For the range of 5 ≤ MB≤ 200, the rate is second order-exponentially decayed with a function of molecular weight of component B, MB. Like the case of a partial pressure of component B, the effects of a molecular weight are reflected through the binary diffusivity coefficients, which are intimately related with suppressing the convection flow inside the growth enclosure, i.e., transition from convection to diffusion-dominant flow mode as the molecular weight of B increases. The convective mode is near at a ground level, i.e.,on earth (1 g0), and the convection is switched to the diffusion mode for 0.1 g0≤ g ≤ 10−2g0, whereas the diffusion region ranges from 10−2g0 up to 10−5
g0.