The diphenylphosphino radical, (C6H5)2˙P

Abstract
The diphenylphosphino radical, (C6H5)2P, has been observed at room temperature in X-irradiated single crystals of triphenylphosphine oxide and diphenylphosphine sulphide and in ultra-violet irradiated polycrystalline diphenylphosphine at 77 K. The isotropic 31P coupling constant is deduced to be +252 MHz and the anisotropic components are approximately 504, -252, -252 MHz. The largest value of the g tensor lies perpendicularly to the direction of the largest hyperfine coupling constant, the values in diphenylphosphine sulphide being 2·0094, 2·0035 and 2·0021. X-irradiated triphenylphosphine oxide also contains the (C6H5)2PO radical.