Abstract
<title>Abstract</title> <p> Peroxo-bond (O <sub>2</sub> <sup>2−</sup> ) is formed from [Y <sub>Z</sub> S <sub>3</sub> ] at [Y <sub>Z</sub> S <sub>3</sub> ] to [S <sub>4</sub> ] transition and molecular oxygen (O <sub>2</sub> ) is formed from the peroxo-bond (O <sub>2</sub> <sup>2−</sup> ) via super oxo-bond (O <sub>2</sub> <sup>−</sup> ) at [S <sub>4</sub> ] to S <sub>0</sub> transition inside the oxygen-evolving complex (OEC) in S-state mechanism. This paper provides the proper logic to explain the mechanism of formation of molecular oxygen (O <sub>2</sub> ) from peroxo-bond (O <sub>2</sub> <sup>2−</sup> ) via super oxo-bond (O <sub>2</sub> <sup>−</sup> ) and return of the S-state cycle into S <sub>0</sub> -state. </p>