Thallium alum

Thallium-alaun, m. thallium alum, -bromiir, n. thallous bromide, thallium(I) bromide, -chlorid, n. thallium chloride, specif, thallic... 

Solubility op Mixtures op Potassium Alum and op Thallium Alum in Water at 25 . 

Caesium Alum. RuUdium Alum. Thallium Alum. ... 

Thallium I) sulphate, TI2SO4. Formed Tl plus hot cone. H2SO4 or TIOH plus H2SO4. Moderately soluble in water forms alums and double sulphates. 

In 1863 R. C. Bottger of Frankfort-on-the Main found that thallium occurs in some spring waters. A certain salt mixture from Nauheim contained, in addition to the chlorides of sodium, potassium, and magnesium, those of cesium, rubidium, and thallium. Since he was able to prepare a thallium ferric alum exactly analogous to potassium ferric alum, he regarded thallium as an alkali metal (72, 73). Although it is sometimes univalent like sodium and potassium, it is now classified in Group III of the periodic system. 

Alum, KAl(S0i)i-l2H20.—Ammonium, rubidium, cesium, univalent thallium, and in some cases sodium may replace potassium, while the aluminum may be replaced by trivalent iron, chromium, indium, gallium, titanium, vanadium but not by the rare-earth metals. 

The Cr1 ion readily forms complexes it exists in aqueous solution as CrfH 0)j. and forms other complexes wilh anions, such asCr(H 0).CI , Crother properties due to variation in the bonding. Compounds or the trichloride have been reported with the following arrangements CrtHjOlsClj. [CrfHiOlsCljCIi- HiO. and [Cr(HiO)4Cf CU2 H 0 Trivalenl chromium also forms double salts, notably the chromium alums, hydrated double salts of Cr(III) sulfate and the alkali metal (or thallium or ammonium) sulfates. 

Salt-Forming Properties. One major difference between potassium and sodium in their salt-forming properties is the much greater ability of potassium to form alums, although potassium does not form quite as many types of these compounds as do the higher alkali metals, or ammonium or monovalent thallium. 

Thallium Rhodium Alum, Tl2S04.Rh3(S04)3.24H20, is somewhat difficult to prepare, partly on account of the small solubility of thallous sulphate. The alum is very soluble in water, and not altogether permanent in air, becoming converted into a whitish powder on prolonged exposure.1... 

Thallium Iridium Alum, Tl2S04.Ir2(S04)3.24H20, crystallises in golden-yellow octahedra.1... 

The metals of the aluminium sub-group are permanent in the air at ordinary temperatures, but when heated in oxygen or the air they become coated with their oxide. The volatility of the metals increases with the atomic weights, and the heavier metals are more easily reduced than those of lower atomic weight. The metals are all malleable, fusible, have small atomic volumes and form hydroxides, M(OH)3, which are typically amphoteric in the first three elements of the sub-group and basic only in the case of thallium. The last four members of the family form alums, and both aluminium and thallium form organo-metallic compounds, resembling zinc in this respect. 

In2(SO<)j is a white solid, very hygroscopic and very readily soluble in water. The simple sulfate forms a hydrate with difficulty, but the ammonium, rubidium, and caesium alums crystallize readily double sulfates resembling the alums but of the composition M Oi In2(SO<) 5 8 H20 have also been prepared with sodium, potassium, ammonium, and thallium. 

Solubility of Caesium Alum, Rubidium Alum, and of Thallium... 

Piccini was obsessed with studying the limiting form of the elements as placed in the periodic table. With this in mind, he took up a new field of research, the synthesis of double sulfates (or alums), a work that enormously stimulated his creativity and enthusiasm [58]. In rapid succession, he prepared the alums of vanadium [59], titanium [60, 61], rhodium [62], manganese [63], iridium, and, finally, of thallium [64] with ammonium and then with the following alkaline metals cesium, mbidium, and potassium. Piccini ably used his method of synthesizing the rhodium sulfates virtually to quantitatively separate rhodium from iridium in solution. Through successive fractional crystallizations, Piccini obtained the alums of rhodium and cesium free of iridium, and through electrolysis of the alums he was able to obtain pure rhodium. 

By itself not particularly strong or durable, aluminum in combination with other metals becomes one of the most versatile materials available. It does take vast amounts of electrical energy to manufacture, however, and presently this involves the production of both carbon dioxide and the sulfur oxides. Alums are astringents and the sources of beautiful crystals. Alumina, the oxide, comes in a variety of polymorphs used as various abrasives and in beautiful, gem-quality minerals. It is also the product of the extremely exothermic thermite reaction. Boron Neutron Capture Therapy (BNCT) offers a potential treatment against brain tumors and other difficult-to-treat carcinomas of the head and neck. Gallium, indium, and thallium compounds do not have many applications. 

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