A carbene is a type of reactive chemical species that contains a carbon atom with only two bonds instead of the usual four. This unique structure gives carbenes a high degree of reactivity, making them important intermediates in various chemical reactions, particularly in organic synthesis. They can exist in two forms: singlet, where the two electrons are paired, and triplet, where the electrons are unpaired. Carbenes can be generated through different methods, such as the decomposition of diazo compounds or the thermal breakdown of certain halomethanes. Due to their reactivity, carbenes are used in creating new compounds and materials, contributing to advancements in fields like medicinal chemistry and polymer science.