Vacuum ultraviolet absorption cross sections for the compounds Cl2, Br2, I2, HCl, HBr, HI, CCl4, CCl3Br, CF3Br, CF3I, HgCl2, HgBr2, and HgI2have been measured between 170 and 230 nm. Studies of the Xe*2discharge lamp used are reported. The absorption bands of various mercuric halides are identified.