Mendelevium was first synthesized in an isotopic form, number 256, by bombarding an isotope of einsteinium with alpha particles in a cyclotron. The alpha particles are composed of two protons and two neutrons and are identical in structure to the nucleus the element helium. Einsteinium is another synthetic element that can only be produced through complex chemical processes including the irradiation of plutonium. Mendelevium is still produced today by using the bombardment of alpha particles on the element einsteinium. These procedures are extremely expensive and complicated; for these reasons, mendelevium is only produced very infrequently and in extremely tiny quantities. The isotopes of mendelevium do not exist for long periods of time, some last less than 5 minutes, and this also complicates the isolation and research on mendelevium. Mendelevium is a radioactive element; while the toxicity effects of mendelevium is not known, it must still be synthesized and handled with great care.