what materials make up the inner core

The inner core, the innermost part of the Earth, is primarily composed of iron (Fe) and nickel (Ni) in an alloy represented by the chemical formula NiFe. This composition is based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earths volume. The inner core is believed to be a hot, dense, and mostly solid ball of iron and nickel, with a radius of about 1,220 kilometers (758 miles).