The extraction of copper(II) chloride from hydrochloric acid into tri-n-butyl phosphate has been studied using G4Cu as tracer. Absorption spectra of the solutions have also been measured. The formulae of the copper complexes extracted at tracer concentration from hydrochloric acid appear to be CuCI~, [H.TBP-3H20] + [CuCI3"2TBP] and [H-TBP'3H~O]2 + [CuC14] 2-. R6sum6--L'extraction de CuCI~, depuis HCI dans phosphate tributylique n, est 6tudi6e au moyen du tracer e4Cu. Les spectres d'absorption des solutions sont par ailleurs 6tablis. Les formules des complexes extraits apparaissent ainsi CuCI~ [H'TBP'3H:.,O]+; [CuC13"2TBP]-et [H'TBP'3H~O]~ + [CuCI4] ~-. Zusammenfassung--Die Verteilung yon Kupfer (1I) zwischen w~issrigen HC1 L6sungen und Tri-nbutylphosphat mittels 64Cu-Isotopen untersucht worden. Die Absorptionsspektren sind auch gemessen worden. Die Formeln der Kupferkomplexe, die aus der w~issrigen Phase bei sehr niedrigen Kupferkonzentrationen extrahiert werden, sind CuCI2, [H'TBP'3H20] + [CuC13-2TBP]-und [H-TBP.3H20]2 + [CuCla] 2 . * Manuscript received 25 April 1963. 823
* This is the range over which the stability constant:;, strictly valid for [HCI], = 0"691 M, might be expected to be reasonably applicable.