The [Au(CH3SO3)4]– Anion in the Crystal Structures of M[Au(CH3SO3)4] (M = Li,Na, Rb)

The reactions of Au(OH)₃, M₂CO₃ (M = Li, Na, Rb), and methanesulfonic acid at elevated temperatures in sealed glass ampoules lead to single crystals of MAu(CH₃SO₃)₄] (M = Li, Na, Rb). In the crystal structures of LiAu(CH₃SO₃)₄] (tetragonal, I$\bar{4}$ , Z = 2,a = 938.64(2) pm, c = 917.01(3) pm, V = 807.93(4) ų) and RbAu(CH₃SO₃)₄] (tetragonal, P$\bar{4}$ 2₁c, Z = 2, a = 946.7(1) pm,c = 889.9(1) pm, V = 797.6(2) ų) the complex aurate anions are linked by the M⁺ ions in three dimensions. Contrastingly, in the structure of NaAu(CH₃SO₃)₄] (triclinic, P$\bar{4}$ , Z = 1, a = 540.04(2) pm,b = 863.75(2) pm, c = 973.29(3) pm, α = 72.694(2)°, β = 75.605(2)°, γ = 77.687(2)°, V = 415.05(2) ų) the complex anions are connected into layers that are further connected by weak hydrogen bonds. The thermal decomposition of LiAu(CH₃SO₃)₄] was monitored up to 500 °C and leads in a multi‐step process to elemental gold and Li₂SO₄.