Compound-formation in the crystalline state was found to be most closely related to the configuration, especially, to the molecular shape of the two components. Molecular compounds of different types were distinguished by the mode of compound-formation, such as the type of phase diagrams, “melting point elevation”, and halochromism.
(1) The gelation times of tung oil catalysed by iodine in various organic solvents were measured. (2) The relation between gelation time t, concentration of tung oil x and amount of iodine z is expressed by the formula logt=ax+b/zx. (3) In the solution having violet tint, iodine has a strong gelation accelerating action, but in the yellowish brown solution the accelerating action of iodine is very weak. (4) Organic acids and nitrobenzene are exceptions of the above fact (3) and in spite of yellowish brown tint, have strong gelation accelerating action. (5) In the iodine solutions of mixed solvents the gelation time increases with the increase of yellowish tint. (6) Difference in catalytic action of iodine solutions is considered to be due to the difference of molecular state of iodine in the solution. Generally solvated solution of iodine has poor catalytic action. (7) Generally iodine in the solvent having high dielectric constant shows strong gelation accelerating action.