Why H2O2 and Not H20?? I was wondering under what conditions hydrogen and Oxygen combine to form H2O2 instead of water. The decomposition of H2O2 into water is exothermic, meaning when we seperate the oxygen atom we have less chemical potential energy. The way it was taught to me, less CPE means more 'stability' (whatever that is). My question is...under what conditions will hydrogen and oxygen combine to form a less stable configuration. I know this abstract idea of stability is dependent on local temp. and pressure but I am not sure in what way or why!! Any insights you can offer would be appreciated. Thanks!