Ph₃AsO, Ph₃AsS, and Ph₃AsSe^- are trapped in X-irradiated single crystals of triphenylarsine chalcogenides. The g tensor and the ⁷⁵As hyperfine coupling tensors are measured for these three radicals and the ⁷⁷Se hyperfine tensor is also obtained for Ph₃AsSe^-. The arsenic spin densities are calculated and the ⁷⁵As coupling eigenvectors are compared with the As=X bond direction in the parent molecule. The results are in accord with a slightly distorted trigonal structure.