a-Aluminas are readily dissolved in concentrated phosphoric acid for analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution rate is significantly faster than with concentrated HCI at high pressure or via fusion techniques. In addition t o the ICP-AES results obtained with these solvent systems, the results of NMR spectrometric analyses are presented, which permit the preliminary characterisation of the species in the phosphoric acid solutions.

The infrared spectra of deuterated (d¡) and protonated tetrakis (di-mandelato(zirconium(IV) and -hafnium(IV) are indicative of a structure containing considerable hydrogen bonding. The neutral stoichiometric tetrakis product from aqueous solution is obtained only with the racemic ligand, suggesting that dl ligand pairs provide a stereospecificity suitable for the formation of stabilizing hydrogen bonds which ligands of one handedness do not provide. A polymeric structure possessing bridging ligand pairs between metal ions is proposed. In acetonitrile, mandelic acid reacts with zirconium tetrachloride by anion replacement, to yield a mixture of monochlorotris(mandelato (zirconium and tetrakis(S-mandelato )zirconium(I V) with an infrared spectrum different from that of the aqueous polymeric product.(1) Abstracted in part from the thesis of E. H. Homeier submitted to the Graduate School in partial fulfillment of the requirements for the Ph.D. degree. Presented in part before the Division of Inorganic Chemistry at the 157th National Meeting of the American Chemical Society, Minneapolis,

Die nach einer Literaturmethode aus wäßriger Lösung erhaltenen Zr‐ und Hf‐ Komplexe (Ia) der dJ‐Mandelsäure haben nach IR‐Untersuchungen festgeleg Strukturen mit Wasserstoffbrücken, die die Stabilität günstig beeinflussen.