Interaction between cation orientation, octahedra tilting and hydrogen bonding in methylammonium lead triiodide

A combined powder diffraction analysis using both synchrotron X ray and neutron diffraction data was used to determine the structure of methylammoni um lead triiodide crystallizing at room temperature in the tetragonal crystal system. The use of rigid body modelling for the methylammonium molecule results in a description of the positions of the hydro gen atoms in the structure, using physically signifi cant bond geometry parameters. In contrast to pre viously available structure models, this allows a meaningful analysis of the pattern of hydrogen bonds and the related distortions of the structur