Singlet Oxygen

**Semantic type:** Inorganic Chemical

**Definition:** An inorganic gas in which all of the electrons are spin paired and the lowest excited state of the diatomic oxygen molecule, with potential cytotoxic activity. Singlet oxygen (sO2) is highly reactive with organic compounds and contributes to the photodegradation of many materials. This property is leveraged during photodynamic therapy (PDT) when sO2 is generated from the triplet ground state of molecular oxygen (O2) and induces oxidative damage and cell death in the targeted tissue.

**Synonyms:** - (1)O2 - 1O2 - 1[O2] - Dioxidene - Singlet Dioxygen - Singlet Molecular Oxygen - sO2