Our goal with this project is to gain insight into the bonding mechanisms of low barrier N-H…N hydrogen bonds and how increased thermal energy changes the charge density distribution of these strong hydrogen bonds. Furthermore we wish to study how the isotope effect manifests itself in the charge density.To study the charge density one need highly accurate and high resolution X-ray diffraction data. However, in this case due to the weak X-ray scattering power of hydrogen/deuterium, neutron data is needed to describe the position and thermal motion of H/D. Both X-ray and neutron diffraction data is combined in one refinement, a so-called X-N charge density refinement. We already have collected high resolution and high quality X-ray data and therefore, we ask for beam time to complete the neutron diffraction experiments.