The preparation and infra-red absorption spectra of several complexes of bis-(2-ethylhexyl)-phosphoric acid

• Published in: Journal of inorganic & nuclear chemistry Vol. 10; no. 3; pp. 275 - 288
• Main Authors: Peppard, D.F., Ferraro, J.R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.1959
• ISSN: 0022-1902; 1878-1225
• DOI: 10.1016/0022-1902(59)80121-4

The bis-(2-ethylhexyl)-phosphates of Li(I), Na(I), K(I), Co(NH 3) 6(III), Co(en) 3(III), Sc(III), Zr(IV), Hf(IV), Th(IV), and U(VI) have been prepared. The mixed nitrate-bis-(2-ethylhexyl)-phosphates of Zr(IV), Hf(IV), Ce(IV), Ce(IV), and Th(IV) were also prepared. The infra-red absorption spectra of all these compounds were obtained, and the antisymmetric POO − stretching vibrations were compared. The POO − stretching vibration frequencies of the bis-(2-ethylhexyl)-phosphates of Sc(III) and Th(IV) were found to be similar to those found for the alkali metal salts and cobaltic salts, indicating high ionic character of the metal to oxygen bond of the phosphate. The bonding to the phosphate of the Hf(IV) and Zr(IV) complexes appears to be of a more covalent character. It is concluded that the nitrate in the mixed compounds is co-ordinated to the metal atom and that the metal-to-nitrate bond is essentially covalent. The bonding to the phosphate in the mixed compounds appears to be different from that in the pure phosphates. Recently the organophosphoric acids have been demonstrated to have interesting solvent properties for various inorganic salts. In particular HDEHP (1–6) has been the subject of several studies in this laboratory and others. The present study involves the extraction from neutral aqueous solutions of the chlorides and nitrates of Sc(III), Zr(IV), Hf(IV), Th(IV), Ce(IV) and U(VI) by HDEHP. The complexes formed in the saturated solutions were determined, and their infra-red spectra were investigated. For comparison, the salts of HDEHP with Li(I), Na(I), K(I), Co(en) 3(III) and Co (NH 3) 6(III) were also prepared and their infra-red spectra obtained.