So let's begin by defining change in Enthalpy affirmation. So loosely speaking, enthalpy affirmation is the energy difference between the final product and its constituent elements. In other words, if this value is negative, that means our final products are stable or more stable than the constituent elements. And in fact, the more negative this value is, the more stable our product is. So let's list a few isomers of hexine. So here's list of five different isomers of hexine and each corresponding change in enthalpy of formation.