The recently discovered hybrid lead iodide materials have captured significant attention due to their application in highly efficient solar cells. The fact that these materials may be deposited from solution may lead to cheap printable solar cells. While most attention originally focussed on methylammonium lead iodide recent record high efficiency cells have used a different organic cations - formamidinium. In this experiment we will study the structure of formamidinium lead iodide over a large temperature range to investigate how the organic cation interacts with the inorganic lead iodide part structure.An understanding this interaction, and coupling it with computational modelling, is central to understanding the way in which these materials absorb sunlight and convert it into electricity