This work involves a study of ground state and photoexcited metal atoms reacting with ethylene, cyclopropane, acetylene and ethylene oxide in an argon matrix at 12°K. The reactions were followed by infrared spectroscopy. Ground state titanium atoms deoxygenate ethylene oxide to yield TiO and ethylene. Both iron atoms and dimers form adducts with ethylene oxide which when photoexcited yield ethylene and the iron oxides. Whereas titanium atoms fail to react with cyclopropane, photoexcited iron atoms and dimers insert into a carboncarbon bond of cyclopropane. Photoexcited iron atoms also insert into a carbon-hydrogen bond of acetylene. Titanium atoms react spontaneously with acetylene to yield a complex. Titanium atoms react with ethylene to form either a three-membered ring or a dicarbene and higher complexes.