PMo//1//20//4//0.

Infrared spectrophotometry has been used to compare the hydrogen-bonding (H-bonding) interactions in solid trialkylammonium salts and double salts. The effect of amine structure on the infrared spectra is minor in all of the compounds studied except that methyl-branching increases the downward shift of the N-H stretching frequency of the salts (R//3NH)Cl; this is interpreted as evidence that methyl branching strengthens the H-bond by decreasing the basicity of the parent amine. Possible relationships between the current results and previously observed solubility patterns are discussed.