Naslov
Extraction and spectrophotometric Determination of Niobium by Tetraphenylarsonium and Phosphonium Chloride from a Hydrochloric Acid Solution

Autori
Tamhina, Biserka ; Gojmerac Ivšić, Astrid

Izvornik
Microchemical Journal (0026-265X) 30 (1984); 178-185

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
extraction; niobium(V); spectrophotometry; tetraphenylarsonium chloride

Sažetak
The extraction of niobium(V) in the form of a chloro complex has been studied. Radiometrical and spectrophotometrical studies show that niobium(V) is extracted practically completely from a solution containing more than 9 mol dm-3 chloride in the range of 2-5 M hydrogen ion concentration by chloroform solutions of tetraphenylarsonium (TPA) and tetraphenylphosphonium (TPP)chloride and that niobium is not extracted at chloride concentrations less than 6 mol dm-3. The mechanism of extraction is based on the formation of the ion-associated compounds that form between the onium cation and the oxotetrachloroniobate(V) anion. The extracted complexes in chloroform have maximum absorbance at 282 nm (TPAS) and 285 (TPP) ; they obey Beer`s law in the range of 1-10 ug Nb ml-1, and are stable for at least 24 hr. The molar absorptivity of the method is 1.33x104 dm3 mol-1 cm-1. The composition of the extracted species [(C6H5)4X [NbOCl4 where X=As or P was determinated spectrophotometrically, radiometrically, and by characterization of the crystalline compounds isolated.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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