Potassium amide (KNH2/KND2) is an ionic molecular crystal. The amide ions (NH2-/ND2-)-isoelectronic with the water molecule OH2-display orientational disorder in the cubic and tetragonal high-temperature phases. In the monoclinic low-temperature phase they are orientationally ordered. We investigated the deuterated compound KND2 in all three phases using high resolution neutron powder diffraction and determined the time-averaged probability density function of the deuterons in detail. The structure of the intermediate tetragonal phase was solved, and deviations of the reorientations of the amide ions in the cubic phase from free rotational diffusion were quantified. From the structural properties of the different phases of KND2 and the structural changes at the phase transitions conclusions on the respective dynamics of the amide ions can be drawn.