nightingale

Hello:) I am interested in structures of hydrates and I want to get information about some hydrate former guest molecules. The reason why I am writing here is to ask whether there is some way of finding the molecular sizes of molecules, such as carbon tetrachloride, trichloroethylene, 1,1,2-trichlorotrifluoroethane and tetrachloroethylene. I will be glad if anyone can recommend a computer program or method to determine the molecular sizes. Thanks:)