Ball-and-stick model of the nicotinamide adenine dinucleotide molecule, NAD⁺, as found in the crystal structure of the zwitterionic form, C₂₁H₂₇N₇O₁₄P₂·4H₂O.

The crystal structure was reported in B. Guillot et al, J. Phys. Chem. B 2003, 107, 9109-9121.

Note that the zwitterionic form is different to the physiological form: the zwitterion is protonated at nitrogen N1 of the adenine group so the molecule as a whole has a charge of zero, whereas the physiological form is not protonated here and thus the molecule has an overall charge of −1.

Colour code:

  Carbon, C: black

  Hydrogen, H: white

  Nitrogen, N: blue

  Oxygen, O: red

  Phosphorus, P: orange