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Outlines of Chemistry: For the Use of Students
Outlines of Chemistry For the Use of Students Author:William Gregory Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHROMIUM AND CHLORINE. a. Sesquichloride of Chromium. CraCl3 = 162'26. Prepared by passing chlorine over a mixture of sesquioxide of chromium and charcoal ... more »heated to redness. It collects in the cold part of the tube as a crystalline peach-blossom-coloured sublimate, which dissolves in water, forming a green solution, which probably contains hydrochloric acid and sesquioxide. Cr,Cl3+3HO = Cr3O3+3HCl. The sesquichloride exists in another modification as a pink insoluble powder. 1.. Oxychloride of Chromium. Cr I 9,?, or Cr Cl, + 2 Cr O,. This compound is formed when neutral chromate of potash, common salt, and oil of vitriol are heated together. (KO,Cr O,) + NaCl+2SO, = (KO, SO3) + (NaO, SO,) + Cr O, Cl; or 3(KO,CrO3)+3NaCl+6SO3=3(KO,SO3)+3(NaO;SO3) + CrCl3+SCrO3. It distils over as a deep-red fuming liquid, which decomposes water, producing hydrochloric and chromic acids. It sets fire to phosphorus and many other combustible bodies. When its vapour is passed through a red-hot tube it is resolved into oxygen, chlorine, and sesquioxide of chromium. 2CrO3 Cl=Cr= O3 +O + Cl, ; or 2(CrCl3 +2CrO3)=3Cr3 O 3 + O, + Cl 0. Its constitution is uncertain, as, according to the two formulae above given, it may be viewed either as chromic acid, in which 1 eq. of oxygen is replaced by chlorine, or as a compound of 1 eq. terchloride of chromium, and 2 eqs. chromic acid. c. Perfluoride of Chromium. When a mixture of chromate of lead, fluoride of calcium, and nil of vitriol, or, better, fuming sulphuric acid, is distilled in a silver retort, there is disengaged a red gas, which, in contact with the moisture of the air, produces hydrofluoric and chromic acids. Its precise composition is unknown. It was formerly considered a terfluoride ; but it appears that this is not the case, and th...« less