In nucleophilic fluorination reactions it is extremely difficult to tune the reactivity of the fluoride anion in organic solution to give the desired product. Building on our work using tertiary alcohol solvents, we are now studying the effect of intermolecular hydrogen bonding on the reactivity profile of the fluoride anion in urea complexes. Through reactivity data, computational analysis and solid state characterisation of alcohol¿fluoride and more recently urea¿fluoride hydrogen bond complexes we have identified characteristics of optimal hydrogen bond donor systems. To further our understanding of this area, we propose a single crystal neutron diffraction study to precisely determine the hydrogen positions of a representative tetraalkyl ammonium fluoride urea complex with the long term goal of developing superior nucleophilic fluorinating reagents for use in synthetic applications.