Alpha particles (named after and denoted by the first letter in the Greek alphabet, a) consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name. The alpha particle can be written as , or (as it is possible that the ion gains electrons from the environment; also, electrons are not important in nuclear chemistry).