The earth's core is primarily made of iron. Inner and outer core differ by physical state, not so much by what they are made of. the terms lithosphere and asthenosphere work in a similar manner. The difference between the two is more related to physical state or behavior than it is to a difference in composition. The lithosphere is brittle or rigid. The asthenosphere is solid but more flexible than the litho. If you want to discuss chemical differences, refer instead to the mantle and crust. The mantle is made of iron and magnesium silicates (Fe Mg Si and O). The chemistry of the crust is more varied. It is made of O Si Al Fe Ca Na K Mg. About 80% of the atoms that make up the crust are oxygen and silicon.
