catena-Poly[[(tetra-hydro-furan-κO)potas-sium]-di-μ-dimethyl-amido-κ(4) N:N-aluminium-di-μ-dimethyl-amido-κ(4) N:N-potassium-di-μ-dimethyl-amido-κ(4) N:N-aluminium-di-μ-dimethyl-amido-κ(4) N:N].

The title compound, [Al2K2(C2H6N)8(C4H8O)] n , formed during the sonochemical reaction between Al(NMe2)3 and sodium-potassium alloy in the presence of tetra-hydro-furan (THF). Its asymmetric unit has two inequivalent K(+) sites. One site is coordinated by a THF ligand, and crystallizes as a one-dimensional polymer with a backbone of catenated AlN2K rings. A twofold rotation axis bis-ects one K(+) site and the THF ligand; the second K(+) site is situated on an inversion centre, resulting in a planar four-coordination by N atoms. The latter symmetry operation generates the second half of the THF mol-ecule and fills out the coordination sphere of the potassium sites. The chains extend along the c-axis direction and zigzag at the THF-coordinated K(+) sites by an angle of 106.02 (5)°.