A "Radical Pair" refers to a pair of molecules or ions that are formed when a single molecule undergoes a reaction that generates two radicals. These radicals are highly reactive species with unpaired electrons, which makes them important in various chemical processes, including combustion and polymerization. The behavior of radical pairs can be influenced by their environment, such as temperature and solvent, affecting their stability and reactivity. In the context of quantum mechanics, radical pairs can exhibit unique properties due to their spin states. The spin of each radical can be correlated, leading to phenomena like quantum entanglement. This has implications in fields such as magnetoreception in animals, where radical pairs may play a role in how certain species navigate using Earth's magnetic field.