A broad-line fluorine magnetic resonance study of the solid addition cornpounds SF,.AsF, and IF, .AsF, slio\?s that each has two types of chemically distinct fluorine in the ratios of 1 :2 and 1:1, respecti\elq. The fine structure and the second moments of the spectra are consistent with the ionic form~~lations SF,+AsF,-and IF,+AsF,-. Bond lengths in the iodine compo~ind are discussed in relation to the observed second moinent at liquid-nitrogen temperature and the calculated rigid-lattice second ~iioment based on the detailed sodium-chloride-type crystal structure of Beaton. The chemical shifts of the fluorines in the three ionic species are measured relative to trifluoracetic acid and to HF. Reorientations of the ions in the solid state are discussed on the basis of the change in second moment with temperature for each compound. A very rough estimate of the anisotropy of chemical shift in I F , -A s F , is made from the slope of the second moment vs. field-squared line at liquid-nitrogen temperature.