Very pure Mg dissolves in liquid NH3 with a blue color. Attempts to isolate solid Mg(NH3)(x) were not met with success. MgHg alloy reacts with liquid NH3 viith formation of Mg(NH3)(6)Hg-22, as established by a single-crystal structure determination. The octahedral Mg(NH3)(6) units have Mg-N distances typical for Mg(NH3)(6)(2+). They are embedded in layers into cavities of the mercury metal matrix, resulting in a layered structure. T-c of this superconducting material is 3.6 K, which is lower than that of pure Hg (4.19 K).