Reaction between [MgCl₂(THF)₂] and [MoOCl₃(THF)₂]. The Crystal Structures of [Mg(THF)₆][MoOCl₄THF]₂ and [Mg₂(m‐Cl)₃(THF)₆][MoOCl₄THF]

Two [MoOCl 3 (THF) 2 ] molecules are used for detachment of two Cl atoms from [MgCl 2 (THF) 2 ]. In such reaction a green crystalline salt [Mg(THF) 6 ][MoOCl 4 THF] 2 IV is formed. Compound IV reacts further with 3 equivalents of bis(tetrahydrofuran)magnesium dichloride, yielding a green ionic [Mg 2 (m̈‐Cl) 3 (THF) 6 ][MoOCl 4 THF] compound V . Compound IV and V vary only in a structure of cation what indicated that the tri‐m̈‐chlorohexakis(tetrahydrofuran)dimagnesium(II) cation in V is really formed in reaction between [Mg(THF) 6 ] 2+ cation and [MgCl 2 (THF) 2 ]. The crystal structure of compounds IV and V has been solved by X‐ray diffraction method. The [Mg(THF) 6 ] 2+ cation forms the tetragonally distorted octahedron with the magnesium atom in the symmetry centre. In homobimetallic di‐octahedral [Mg 2 (m̈‐Cl) 3 (THF) 6 ] + cation the magnesium atoms are surrounded by three bridging chlorine atoms and three THF molecules. The structures of [MoOCl 4 THF] − in IV and V are similar. In those anions the molybdenum atom is hexacoordinated with four chlorine atoms in equatorial plane.