The structure of C3O2 (carbon -2 +2 0 +2 -2 suboxide) is O = C = C = C = 0 each of the two terminal oxygen atoms have an oxidation state of -2 and the carbons to which they are attached have an oxidation state of +2. (Since when ever a covalent bond is formed between similar atoms, each of the atoms is given an oxidation state of zero), therefore, the oxidation state of central carbon atom in C3O2 is zero.
Thus, the two terminal carbon atoms are present in +2 oxidation state each, whereas the third one is present in zero oxidation state. Therefore, the average oxidation state of carbon in
