Hi guys, I'm having a bit of difficulty understanding Pourboix diagrams. The biggest problem at the moment is that I don't clearly understand what exactly the E° values on the y-axis are of. All the resources I've consulted haven't been especially clear about this. Sometimes they make it sound as though they are some sort of "environment" potential - but what exactly this means, I'm not too sure. In other places they're made to sound like E° values of the reduction of the relevant species compared to SHE, but a reduction to what exactly, I'm not sure either. In a related problem, I don't understand whether we discern E° and what the most stable species present is for a given pH, or whether we only discern what the most stable species present is from a combination of pH and mystical E° information. Would anyone be able to help? Any assistance would be greatly appreciated! Hopefully my questions are clear enough... Thanks!