The crystal structure of sodium bis(trans)-2-methylpropanedionatedimethanolaluminate(III), [Na+][Al(C4H4O4)(2)(CH3OH)(2)(-)], has been determined by single crystal X-ray diffraction. The compound crystallises in the trigonal space group R (3) over bar, with a = 12.046(2), c= 28.705(6) Angstrom and Z= 9. The refinement of 103 parameters on 946 reflections [1>2.0 sigma(I)] gave a final R-value of 0.064 (R-w= 0.066, S= 1.000). The structure consists of octahedral Al(C4H4O4)(2)(CH3OH)(2)(-) complexes and sodium ions. In these complexes, methylmalonate coordinates to Ak(3+) bidentately in the equatorial plane of the octahedron, while methanol coordinates at the apices. As such, it represents a rare single-crystal example of direct aluminium( III)-methanol coordination. The complexes, arranged in layers, are connected to each other by octahedrally coordinated sodium ions, in special position 6c, and hydrogen bonds. The layers, with the methyl group of methylmalonate pointing out from the layers, are stacked perpendicular to the  direction and are held together by other octahedrally coordinated sodium ions, in special position 3b.
1998. Vol. 52, no 9, 1116-1121 p.