Structures of Dimethyl Ether and Methyl Alcohol

Abstract

The molecular structures of dimethyl ether and methyl alcohol were determined in gaseous state by means of the sector‐microphotometer method in electron diffraction. The structural information was derived from the resolution of radial distribution curves. It was confirmed that a dimethyl ether molecule exerts hindered internal rotation with a potential minimum at the C_2v configuration. The most probable values for the bond distances and the bond angles are for dimethyl ether: C–O = 1.416±0.003 A, C–H = 1.094±0.006 A, ∠COC = 111.5°±1.5°; and for methyl alcohol: C–O = 1.428±0.003 A, C–H = 1.095±0.010 A, O–H = 0.960±0.015 A, ∠COH = 109°±3°. The results on methyl alcohol agree with those of microwave determinations. The observed values of vibrational amplitudes are in good agreement with those computed theoretically.