A TRIS(OXALATO) TITANIUM(III) COMPLEX - THE PREPARATION AND STRUCTURE OF POTASSIUM AQUATRIOXALATOTITANATE(III) TETRAHYDRATE

Potassium aquatrioxalatotitanate(III) tetrahydrate has been prepared by the addition of excess potassium oxalate to an aqueous solution of hexaureatitanium(III) chloride. The crystal and molecular structure has been determined by single-crystal, X-ray diffractometry (Mo Kα radiation, 0.7107 Å) and found to be orthorhombic, with unit cell dimensions: a = 20.746(3), b = 11.532(2), c = 7.328(2) Å, space group Pnma and Z = 4. The anionic complex consists of a distorted pentagonal-bipyramidal arrangement of seven oxygen atoms around the titanium atom. One axial oxygen atom is provided by the coordinated water molecule and the rest by chelating oxalate ions of which two are in the equatorial plane. Observed bands in the diffuse reflectance spectrum at 9600 and 12 200 cm-1, attributed to dd electronic transitions, are discussed in relation to the structure. © 1990.