Cyanocobalamin is the most common and widely produced form of the chemical compounds that have vitamin B12 activity.
For example, the hadron constituents of atomic nuclei, neutrons and protons, have charges of 0 e and +1 e respectively; the neutron is composed of two down quarks and one up quark, and the proton of two up quarks and one down quark.
In most lighter elements the nucleus of each atom has the same number of protons and neutrons. but heavier elements have more neutrons than protons. Uranium, for example has 92 protons and 146 neutrons.