It is the molecules surrounding the metal that determine how reactive the compound is. (newscientist.com)
The elements then form ozone, nitrogen oxide and other reactive compounds that can kill off bacteria and cancer cells. (scientificamerican.com)
Antioxidants are widely believed to protect cells by sopping up highly reactive compounds known as free radicals before they have a chance to react and tear apart DNA or other vital cellular components. (sciencemag.org)