Chemistry can be quite confusing. In order for the desired substance to be produced in a reaction or for two substances to interact - or not - chemists have to take into account a number of factors. Researchers at the Fritz Haber Institute of the Max Planck Society in Berlin can now offer them additional access. They have measured how strongly electrons are bound when they are put into water – namely right at the start as soon as the negative charge carriers are released by, for instance, a potential reaction partner. Electrons are the actual players in chemical reactions, as they are moved between different atoms during this process. Whether that happens depends on their binding energy to the different components. And in reactions in aqueous solutions, the binding energy of an electron at the beginning of the solvation process is a key factor. Now that it is known, chemists can consider it when planning or preventing reactions.