The reactions of scandium atoms and methanol molecules have been investigated by matrix isolation infrared absorption spectroscopy. The reaction intermediates and products were identified on the basis of isotopic IR studies with (CH3OH)-C-13, (CH3H)-H-18, and CH3OD, as well as density functional theory calculations. In solid argon, the ground-state scandium atoms reacted with methanol to form the inserted CH3OScH molecules spontaneously but not the thermodynamically more favorable CH3ScOH. The inserted CH3OScH molecule underwent photochemical rearrangement to form the (CH4)OSc complex upon ultraviolet-visible irradiation. In addition, the CH3OSC molecule and its photoinduced CH3ScO isomer were also observed.