Experimental charge density of alpha-glycine at 23 K

The electrostatic properties of crystals of or-glycine have been obtained f rom extensive X-ray diffraction data collected at approximately 23 K and ca refully processed, including corrections for scan truncation losses, anisot ropic extinction, and multiple reflection. From a multipole parameterizatio n of the X-ray intensities we have obtained an unusually precise-and we are confident, accurate-model of the total electron distribution in the crysta l including the topological features, atom and group charges, the dipole mo ment for the glycine zwitterion, electrostatic potentials, electric field g radients at the nucleii of the three hydrogen atoms of the ammonium group, and intermolecular electrostatic energies within the crystal. We have also calculated the total interaction energies involving the six distinct types of intermolecular pairings and examined these energies in terms of the mole cular arrangement.