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LaF2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. La2+ is bonded in a body-centered cubic geometry to eight equivalent F1- atoms. All La–F bond lengths are 2.56 Å. F1- is bonded to four equivalent La2+ atoms to form a mixture of edge and corner-sharing FLa4 tetrahedra.
Both the transmittance and reflectance of 2 mm thick MgF2 substrates and of thin films of BaF2, CaF2, LaF3, MgF2, Al2O3, HfO2, and SiO2 deposited on these substrates were measured for the wavelength range 120 nm to 230 nm. Results for BaF2, LaF2 and MgF2 show promise as being good materials from which interference filters can be made. The software and related hardware needed to take large amounts of data automatically in future measurements of the transmittance and reflectance was developed.