Characterisation of the first authenticated organomercury hydroxide, 4-Me2NC6H4HgOH

4-Me2NC6H4HgOH was prepared from 4-Me2NC6H4HgOAc. Full characterisation showed that it crystallises as discrete molecules, the first example of a true organomercury hydroxide in the solid state. The structures of 4-Me2NC6H4HgOAc and (4-Me2NC6H4)2Hg are also discussed.