The techniques of x-ray diffraction of liquids are employed to study the salt TlCo(CO)4 in two solvents, tetrahydrofuran and dimethylsulfoxide. Radial distribution functions calculated from scattering data are analyzed in terms of the structure of these solutions, and the results are compared to those of other studies of the same and similar solutions investigated by infrared techniques. In tetrahydrofuran, a solvent of low dielectric constant, the evidence indicates close association of anion and cation, and contact ion pair and covalent models are presented and discussed. In dimethylsulfoxide, a solvent of high dielectric constant, the evidence indicates relatively loose association or no association of anion and cation, and solvent-separated ion pair and free ion models are presented and discussed.