The analysis of beryllium and beryllium oxide—VI☆The determination of tantalum and niobium

Electrochemical and spectrophotometric study of isomeric stilbenediol intermediates in the reduction of benzil in acid solution

“…Observations at Low pH. Electrolysis of benzil at -0.950 V vs. SCE in 48% ethanol or 50% methanol, pH = 1.0, produced a single electro-oxidizable intermediate (trans) as predicted by previous work (2,3). Typical spectrophotometric results are shown in Figure 1.…”

NONFERROUS METALLURGY. II. Zirconium, Hafnium, Vanadium, Niobium, Tantalum, Chromium, Molybdenum, and Tungsten

“…Volodarskaya and Derevyanko (276) titrated zirconium to the xylenol orange end point after removing the interference of iron (III) by reducing it with hydrox- Arsenazo III: Study of conditions and/or interferences (2/3); ; Ti, Th, Fe, Ca, Mg (269); Zr, Hf, Pa, Sc, Th, U mixtures (244,245) Sodium alizarin sulfonate: U (119,121); Tí (71,288); study of conditions and/or interferences (214) Purpurogallin: Study of conditions and/or interferences (73); Fe (8) Chlorophosphinazo III: Study of conditions and/or interferences (85) 8-Quinolinol: U (193) Flavinol-2'-sulfonic acid: Study of conditions and/or interferences (204) Galangin: Study of conditions and/or interferences (135) V,V'-di-(2-hydroxy-5-sulfophenyi)-c-cyanoformazon: Study of conditions and/or interferences (273) Molybdosulfatozirconate: Study of conditions and/or interferences (67) Methylthymol blue: Study of conditions and/or interferences (52) Arsenazo III: Zr, Hf, Pa, Sc, Th, U mixtures (244,245) Mandelic acid, chloranilic acid, quercetin, xylenol orange: Zr (127) Xylenol orange: U (37) Vanadium(Y) ion: Study of conditions and/or interferences (2/2) Vanadium(II), (III), (IV) ions: Study of conditions and/or interferences (180) Vanadate and vanadyl ions: Study of conditions and/or interferences (90) Phosphotungstovanadic acid: Cr, W, V (286); A1 (31) 8-Quinolinol: Study of conditions and/or interferences (171); U (17) Catechol: Complex alloys Pyrogallol: Mo, W, Cr (46); minerals and ores (279) Hydroquinone: Be, BeO (115) ylammonium chloride. Tsuchiya (270) titrated zirconium and hafnium with EDTA to the xylenol orange end point in a boiling solution containing 0.9 ± 0.3 hydrochloric acid.…”

“…These same authors (47) eliminated the fluoride interference in the pyrogallol method for tantalum by the addition of boric acid and eliminated the vanadium interference by extraction of the tantalum-pyrogallol complex into ethyl acetate in the presence of Ethoquad 18/25. Hibbits et al (115) determined tantalum with pyrogallol and niobium with hydroquinone in beryllium and beryllium oxide after first precipitating them with cupferron and then separating them on a strongly basic ion exchange resin. After a systematic study, Ackermann and Koch (1) recommended tribromopyrogallol as a selective and sensitive reagent for niobium.…”

Nonferrous Metallurgy

“…Hibbits et al (75) reported the determination of cadmium in beryllium and beryllium oxide by precipitating cadmium from an ammoniacal solution with benzotriazole and nickel as a collector and converting to a chloride solution. The cadmium was then separated by an anion exchange resin, eluted, and extracted with dithizone in CHCI3, which was measured at 518 µ.…”