On the errors in molecular dipole moments derived from accurate diffraction data

The error in the molecular dipole moment as derived from accurate X-ray dif fraction data is shown to be origin dependent in the general case. It is in dependent of the choice of origin if an electroneutrality constraint is int roduced, even when additional constraints are applied to the monopole popul ations. If a constraint is not applied to individual moieties, as is approp riate for multicomponent crystals or crystals containing molecular ions, th e geometric center of the entity considered is a suitable choice of origin for the error treatment.