so would you expect the allotropes of carbon that's Diamond graphite and c6d but Minster ferine to have the same eny change of formation in standard conditions well so don't forget allotropes are different forms of the same element that's the definition and the definition of uh enthalpy change of formation is the enthropy change when one mole of a substance is produce from its elements in their standard State at standard ambient temperature and pressure so the standard state of carbon is graphite so if I turn a graphite into graphite essentially achieving nothing the standard State into graphite it is the standard State then it comes out at zero there's no enthalpy change there but looking at Diamond and bminer ferine they are endothermic so that means that when you turn graphite into diamond or bminer ferine more energy is needed to break the bonds than is released when you make the bonds this is an endothermic reaction so don't forget endothermic looks like that and the products have higher energy and if the products have higher energy that must mean they're less stable so something with lower energy down here is stable and that would be the graphite and the unstable ones have higher energy so that means that butman ferine and Diamond are less stable you need to add energy overall to make them so why is that what is it about these two molecules here that make them less stable than graphite so the easier one to examine is the but Minster ferine the carbon atoms they have SP2 hybridization and they're wrapped up in that sphere shape and this causes strain on the bonds now the bond angle is less than 120° preferred by the SP2 and those bonded electrons are forced closer together and that's going to need more substantial input of energy to put those electrons where they don't want to go to fight that repulsive uh Force there onto Diamond that's a little more subtle the different number and type of bonds along with the different packing of the atoms mean that diamonds requires just a tiny amount of energy overall if you're going to make it from graphite and apparently if you leave Diamond long enough and you heat it hot enough it will rearrange itself into graphite again which is the lower energy one and we're done