Treatment of (2,4,6-^tBu₃C₆H₂)P=P(2,4,6-^tBu₃C₆H₂) with CF₃SO₃Me gives a salt A as the only product. The ³¹P NMR spectrum of the precursor contains a singlet (δ+495 ppm), while that of the product exhibits two doublets (δ+237 and +332 ppm, J = 633 Hz). Compound A reacts with MeLi to give two isomers of B which are in equilibrium in solution. The solution ³¹P NMR spectrum of B at 298K shows one broad signal. On cooling to 213K, two signals at δ–32:4 and –35.8 ppm are observed. From the solid state structures of A and one isomer of B, the P–P bond lengths are 202 and 222 pm. Suggest identities for A and B, and draw their structures which show the geometry at each P atom. Comment on the nature of the isomerism in B.