In the atmosphere it will be lost because of reaction with photochemically produced hydroxyl radicals. Carbophenothion can be degraded in the atmosphere by a reaction with photochemically produced hydroxyl radicals. It is photochemically unstable in solution. Polymers containing light absorbing elements can serve as photochemically controlled artificial muscles. From 1-aminopyridinium salts the photochemically active 1-"N"-iminopyridinium ylides are accessible by acylation. It decomposes thermally and photochemically to tetraiodoethylene, CI. Paquette demonstrated that vinylcyclopropane rearrangements can also be mediated photochemically. Various photochemically active light absorbers are present in surface waters, enhancing indirect phototransformation. It can be converted to "cis"-stilbene photochemically, and further reacted to produce phenanthrene. The luminescence is photochemically stable and its quantum yield is ~0.65. The substitution of CO ligands can be induced thermally or photochemically by donor ligands. Biomimetic chalcogels containing FeS clusters were reported to reduce photochemically N to NH. Phenanthrene can also be obtained photochemically from certain diarylethenes. NOCl and cyclohexane react photochemically to give cyclohexanone oxime hydrochloride. Iron pentacarbonyl reacts photochemically with alkenes to give Fe(CO)(alkene).