IIAB group meteorites are Hexahedrites or coarsest Octahedrites, which consist of large Kamacite crystals with minor Taenite. These are examples of the broadest (Ogg) known nickel-iron crystal structure, and generally have the lowest nickel content of the iron meteorites.
The trace element concentration of these meteorites is similar to some Carbonaceous Chondrites and Enstatite Chondrites so they probably are fragments of a C-type asteroid.

Manzanita Lab offers IIAB group specimens from the February 12, 1947 fall in the Sikhote Alin Mtns., Maritime Province, Russia, about 270 miles northeast of Vladivostok. The Sikhote Alin meteorite entered the earth's atmosphere with a cosmic speed of about 31,000 miles per hour. There are two types of specimens associated with this fall, complete individuals that broke off at high altitude while still at cosmic speed, and fragments derived from the final explosion at an altitude of about 3.5 miles or from hitting the earth's surface.

Structural Class: Coarsest octahedrite, Ogg, Widmanstätten bandwidth 9.5 mm.
Chemical class: Group IIAB, 5.9% Nickel, 0.42% Cobalt, 0.46% Phosphorus, about 0.28% Sulfur, 52 ppm Gallium, 161 ppm Germanium, 0.03 ppm Iridium.