Syntheses and crystal structures of tetramethylammonium diaquatetrafluoromanganate(III) and rubidium aquatetrafluoromanganate(III)

Abstract

The crystal structures of the title complexes, [NMe₄][ MnF₄(OH₂)₂](1) and Rb[MnF₄(OH₂)](2), have been determined by three-dimensional Patterson–Fourier and least-squares methods based on X-ray (Mo-K_α) diffraction data. Complex (1) has been isolated from an aqueous solution of the corresponding fluorides. It crystallizes in space group C2/c with a= 16.092(3), b= 5.559(1 ),c= 10.844(2)Å, β= 97.59(2)°, Z= 4, and R= 0.033. The structure consists of [MnF₄(OH₂)₂]^– anions, which are tetragonally elongated octahedra, linked by hydrogen bonds to form layers parallel to x00 planes with tetramethylammonium cations between the layers. Complex (2) crystallizes from acid solution as monoclinic crystals of space group C2/c with a= 13.932(2), b= 6.471(1), c= 10.635(1)Å, β= 105.54(1)°, Z= 8, and R= 0.037. The structure consists of [MnF₆]^3– and [MnF₄(OH₂)₂]^– octahedra alternating in the ac direction. Rubidium cations as well as hydrogen bonds bind the anion chains together. The observed distortion of the octahedra in both structures is ascribed to the Jahn–Teller effect.