Except that methyl mercaptan is a gas at room temperature, other mercaptans are liquid or solid. The thiol molecules have dipole attraction, but are less than the dipole attraction between the alcohol molecules, and there is no obvious hydrogen bonding between the thiol molecules, and there is no obvious association. Therefore, the boiling point of the thiol is higher than that of the alkane having a similar molecular weight, lower than that of the alcohol having a similar molecular weight, and similar to the thioether having a similar molecular weight.

Thiol does not form a good hydrogen bond with water, so the solubility of mercaptan in water is much smaller than that of the corresponding alcohol. At room temperature, the solubility of ethanethiol in water is only 1.5g/100mL.

Low-grade mercaptans have a strong and disgusting odor, and the odor of ethanethiol is particularly pronounced, so ethanethiol is commonly used as a warning agent in natural gas to warn of natural gas leakage. However, as the molecular weight increases, the odor of the mercaptan becomes weaker, and the mercaptan of more than nine carbons has a pleasant odor.