COMPARISON OF THE SPECIES FORMED UPON BASE HYDROLYZES OF GALLIUM(III) AND IRON(III) AQUEOUS-SOLUTIONS - THE POSSIBILITY OF EXISTENCE OF AN [FEO4FE12(OH)24(H2O)12]7+ POLYOXOCATION

The hydrolytic behaviour of iron(III) has been investigated. The infrared spectrum of the sulfate salt of a hydrolysed iron(III) solution was found to match that of a gallium sulfate that had been shown through magic angle spinning NMR spectroscopy in combination with powder X-ray diffraction studies to contain the Ga13 ion. This supports the view that an [FeO4Fe12(OH)24(H2O)12]7+ ion forms. It appeared, however, that this Fe13 ion is extremely unstable and decomposes very rapidly in solution. The addition of small amounts of Fe(II) ions seems to stabilize the structure somewhat, however, and allowed it to be used as a clay mineral pillaring agent. The resulting d001 spacing of ca. 19.3 angstrom is similar to that seen in similar studies of [GaO4Ga12(OH)24(H2O)12]7+.