Plutonium-241 (241Pu, Pu-241) is an isotope of plutonium formed when plutonium-240 captures a neutron. Like all plutonium isotopes (but especially 239Pu), 241Pu is fissile, with a neutron absorption cross section about 1/3 greater than 239Pu, and a similar probability of fissioning on neutron absorption, around 73%. In the non-fission case, neutron capture produces plutonium-242. In general, isotopes with an odd number of neutrons are both more likely to absorb a neutron, and more likely to undergo fission on neutron absorption, than isotopes with an even number of neutrons.