This problem is avoided if E correction (composition) smoothly approaches zero as the reference state is approached. The standard correction method aimed to achieve this by only correcting anions. The number of anions in the structure should decrease smoothly to zero as the reference state is approached; however, in order to correct only the anions, one needs to be able to guess the oxidation state of the atoms in the structure, which is non-trivial and unreliable. This problem is described in the next section, "problem 2."