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 infra red spectrum of the sulfate salt of a hydrolysed iron(III) solution wa s found to match that of a gallium sulfate that had been shown through magic angle spinning NMR spectroscopy in combination with powder X-ra y diffraction studies to contain the Ga13 ion. This supports the view that an [FeO4Fe12(OH)24(H2O)12]7+ ion forms. It appeared, however, tha t this Fe13 ion is extremely unstable and decomposes very rapidly in s olution. The addition of small amounts of Fe(II) ions seems to stabili ze the structure somewhat, however, and allowed it to be used as a cla y mineral pillaring agent. The resulting d001 spacing of ca. 19.3 angs trom is similar to that seen in similar studies of [GaO4Ga12(OH)24(H2O )12]7+.