Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![.§ 104.] ZIRCONIA. 2. Thoria, ThO^ [ThO,]. mi- • • „ ^^y^ vnrfl flartli found in thorite and monacite. It is white, Thonais a very iaaeeaitbto^^^^ ^^^^^^^ ^^^^^.^^ or gray.. If the eaith ^^^^Jj^^^ g ^ sulphuric acid and 1 part of water; .vith a mixture of I pitot conc^^^^ 1 fusion with alkalies. When \^Wd bv ieni?*n^^ hydrochloric thoria ^Z;,^^^^^^^^ are left in I varnish-like form, which From solutions of thoria salts, potassa, ammonia, and sulphide of am- moSum precipitate the white hydrate, which is insoluble m an excess of Se^S ant, even of potassa (difference between thona and alumma and beryllia); tartaric acid prevents the precipitation. Carbonate of potass7and carbonate of ammonia precipitate basic carbonate of thoria, Shich readily dissolves in an excess of the precipitant m concentrated solu- tions- with difficulty, however, in dilute solutions (difierence between thona and Llumina). Erom the solution in carbonate of ammonia, basic salt separates again even at 50°. Carbonate of baryta precipitates thoria completely. Hydrofluoric acid precipitates the fluoride which at first appears gelatinous, but after a little while pulverulent; the precipitate is insoluble in water and hydrofluoric acid. (In this respect thoria differs from alumina, beryllia, zirconia, and titanic acid.) Oxalic acid produces a white precipitate (in this thoria difiers from beryllia and alumma); the precipitate is not soluble either in oxaHc acid or m dilute mineral acids, hut it dissolves in a solution of acetate of ammonia containing free acetic acid (in this thoria difiers from yttria and protoxide of cerium) The pre- <;ipitate is soluble in a boiling solution of oxalate of ammonia, and is not re- precipitated on diluting the solution and allowing it to stand (difierence from cerium, lanthanum, didymium, and yttrium, Bunsen). Sulphate of potassa in concentrated solution precipitates thoria slowly but com- pletely (in this thoria differs from alumina and berylha). The precipitate consists of the double sulphate of potassa and thona ; it is insoluble m concentrated solution of sulphate of potassa; it dissolves with difficulty in cold but readily in hot water. On heating the neutral solution of sulphate of thoria in cold water, it separates in the form of a heavy white curdy pre- cipitate (difference between thoria and alumina and beryllia). This precipi- tate redissolves in cold water (in which it differs from titanic acid). On boiling a neutral or slightly acid solution with hyposulphite of soda, hyposulphite of thoria is precipitated mixed with sulphur; the precipitation, however, is not quite complete (difference between thoria and yttria and oxide of didymium). 3. Zirconia, ZrO, [ZrOJ. Found in zircon and some other rare minerals. A white powder insoluble in hydrochloric acid, but after continued heating with a mixture of 2 parts of hydrated sulphuric acid and 1 part of water it is soluble in water. Soluble zirconia salts are also obtained on fusing it with the bisulphates of the alkalies or with hydrofluoride of potassium. The hydrate resembles hydrate of alumina, dissolving readily in hydrochloric acid when precipi- tated cold, and still moist, but with difficulty when precipitated hot, or after drying. The soluble zirconia salts redden litmus. The native silicates of zirconia may be decomposed by fusion with carbonate of soda; the finely](https://iiif.wellcomecollection.org/image/b21966953_0133.jp2/full/800%2C/0/default.jpg)
