The few members of the IIF iron meteorite group are all nickel-rich, and thus structurally representing plessitic octahedrites to ataxites.
Formation history & Origin: Besides the abundance of nickel, the IIF iron meteorites do contain high amounts of gallium, germanium, copper, and cobalt, indicating that formation occurred in the core of a differentiated asteroid. The oxygen isotopic compositions of the IIF irons are similar to those of the Eagle Station pallasites, and probably both groups share a common parent body. A similar oxygen isotopic composition is also displayed by the carbonaceous chondrites of the CO/CV clan, suggesting a formation of the IIF/ESP parent body in the outer regions of the asteroid belt.
Members: Group IIF consists of just five members. Renowned IIF irons are the meteorites of Del Rio, Monahans (1938), and Repeev Khutor, the latter representing the only witnessed fall of the group that occurred in Russia in 1933.