ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Binary Molten Acetamide—Alkali Metal Iodide Eutectics - the Solution Chemistry of Seven First Row Transition Metal Compounds

D. H. Kerridge and E. I. Eweka

Department of Engineering Materials, University of Southampton, Highfield, Southampton, SO17 1BJ United Kingdom

Abstract: Partial binary phase diagrams with eutectic compositions and temperatures were determined for acetamide-potassium iodide, acetamide-sodium iodide, and acetamide-lithium iodide; together with the densities of these eutectics from their melting points to 100°C.The reactions of seven first row transition metal compounds were examined in acetamide-potassium iodide eutectic and one in acetamide-sodium iodide eutectic. Iodide was found to coordinate to the highly soluble cobalt(II) salts at 60°C, giving electronic spectra typical of octahedral coordination with probably three oxygen-bonded acetamido ligands and three iodo ligands. With increasing temperature, up to 140°C, the spectrum increasingly became that of four coordinate tetrahedral cobalt(II), probably with one acetamido and three iodo ligands. Cobalt(II) sulfate gave very similar spectra.Chromium(III) chloride and nickel(II) chloride showed limited solubility and were principally coordinated by acetamide. Four other compounds were reduced, anhydrous copper(II) sulfate and iron(III) chloride forming brown triiodide (I₃^-) solutions containing copper(I) iodide precipitate and coordinated iron(II) cations, respectively. Potassium chromate and potassium dichromate were very slightly soluble, initially forming yellowish/pale orange solutions, which contained more chromium(III) as temperature and/or the time increased.

Full paper in Portable Document Format: 522a71.pdf

Chemical Papers 52 (2) 71–75 (1998)