Volume 1

Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors.

Date:: 1888-1894

Credit: Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors. 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.

751/796 (page 725)

$Cerous bromide. Ce,Br6 or CeBr3. Known as the hydrate CeBr3.a:H20. Obtained by dis- solving cerous oxide, Ce203, in HBrAq and evaporating. Deliquescent needles ; unchanged by heating out of contact with air; heated in air, partially decomposed with loss of Br. Forms double salt CeBr3.AuBr3.8H.,0 (John, Bl. [2] 21, 323). Cerous chloride. Ce,Cl5 or CeCl3. Ob- tained by heating Ce in CI; or by dissolving Ce,03 in HClAq, adding NH4C1, evaporating to dryness, and driving off NH4C1 by heating; or by passing a mixture of dry CO and CI over hot Ce203 (Didier, C. R. 101, 882). Pure CeCl3 was prepared by Robinson (Pr. 37, 150) by heating pure Ce,(C,04)3 in pure dry HC1 gas to 120°-130° for some time, then to 200°, and then to low redness ; the small quantity of C separated was removed by heating at low redness in mixed C02 and HC1; finally the temperature was raised to a full red heat and the C02 stream was stopped. The chloride was allowed to cool in HC1 gas, transferred to a small flask, and kept in vacuo, over H,S04 and surrounded by CaO, until all HC1 was removed. S.G. }|f 3-88 (Robinson, I.e.). A white, deliquescent solid; easily soluble in water with production of heat; decomposed by 0, or by steam, to Ce203 (Didier). A hydrate, CeCl3.7H20, is said to be formed by digesting Ce203 in HClAq and evaporating. Various double salts are described; e.g. CeCl,.4HgC1...10H.,O, CeCl3.PtCl4.13H,0, CeCl3.AuCl3.13H.,0 (Jolin, he). Cerous cyanide (and double cyanides) v. Cyanides. Cerous fluoride. CeF3. Obtained as a gelatinous pp. (2CeF3H.,0) by adding NaFAq to CeCl3 in HClAq (Jolin). Ceric fluoride. CeF4.H,0. An amorphous brown powder, insoluble in water, obtained by treating Ce02.6H20 with HFAq, washing, and drying at 100°. Decomposed by heat with loss of H20 and HF and formation of CeF3; heated strongly in contact with moist air Ce02 and HF are formed. Combines with KF (by treatment with KF.HF) to form 2CeF,.3KF.2H,0 (Brauner, C. J. 41, 69). Cerous iodide. Ce2l\ or Cel.,. Obtained as the hydrate CeI.,.9H,0, in colourless crystals, by dissolving Ce263 in HIAq, evaporating in a current of H,S, and placing in vacuo over H,S04: soluble in water and alcohol, very quickly decomposes in air (Lange, J. pr. 82, 134). Cerium oxychlorides. The compound Ce,03ClG (= Ce,0.,.2CeCl3) is said to be formed when CeCl3 is heated with Na (in preparation of Ce) and the mass is treated with water. Dark purple, lustrous, powder; insoluble in water (Wohler, A. 144, 254). The same oxychloride is said to be obtained, as iridescent scales, by passing a mixture of steam and N over a fused mixture of CeCl3 and NaCl; easily soluble in dilute acids; heated in air gives Ce.,03 and HC1 (Didier, C. B. 101, 882). Cerium, hydroxides of, v. Cerium, oxides of. Cerium, oxides and hydrated oxides of. The best studied oxides are cerous oxide Ce203, and ceric oxide Ce02; a peroxide CeO, also pro- bably exists. Other oxides, e.g. Ce205 and Ce^,, have been described, but their existence is very doubtful. Cerous oxide. Ce203. (Cerium sesquioxide.) Mol. w. unknown. The white, bulky pp. ob- tained by adding KOHAq to a solution of a cerous salt is hydrated cerous oxide ; as the pp. at once begins to take up O and CO, from the air the hydrate has not yet been obtained pure. The oxide Ce,0:i is prepared by heating cerous oxalate in a stream of pure H. The oxalate is prepared from the basic nitrate (v. Cerium, Pre- paration) by dissolving in a little HN03Aq and ppg. by oxalic acid (Popp, A. 131, 361; Ram- melsberg, B. 6, 86). Properties and Reactions.—A grey solid; unchanged by heating in H. Dissolves in many acids to form cerous salts of the form Ce,X3, X = S04, C03, 2NO.„ 2C10„ &c. Ceric oxide. Ce02. (Cerium dioxide). The pale yellow pp. obtained by suspending Ce„03.:cH,0 in IvOHAq and passing in CI is hy- drated ceric oxide (2CeO.,.3H.,0 ; Rammelsberg, P. 108, 40). Formation.—1. By washing the hydrate with water containing a little acetic acid until KOH is removed, drying and heating.—2. By heating cerous sulphate Ce,3S04 to full redness in air. 3. By heating CeF4 in air (Brauner). Preparation.—Cerous oxalate is prepared from the basic nitrate from cerite (v. Cerium, Preparation); it is heated to redness in a Pt dish with free access of air. Nordenskiold (P. 114, 616) obtained colourless, transparent, tesseral crystals of Ce02 by heating Ce02 for 24 hours with a little borax in a porcelain oven, and treating the mass with HClAq: S.G. at 15° = 6-94. Proper-ties and Reactions.—Very pale yellow solid (Wolf, Brauner, Robinson [C. N. 54], Crookes, Pr. 38, 414). S.G. 6-74 (Nilson a. Pet- tersson, B. 13, 1459). S.V.S. 25-45. S.H. •0877 (N. a. P., Pr. 31, 46). Dissolves in cone. H,SO.Aq with production of much heat, and evolution of some O ; on crystallising, the salt Ce23S04.Ce(S04)2.24H20 separates (Mendelejeff, A. 168, 45); from the mother-liquor of this salt ceric sulphate Ce2S04.4H20 is obtained. This reaction shows that part of the Ce02 is re- duced by the H2S04 to Ce203, and part reacts with the acid to form Ce2S04. Dissolves in HN03Aq; on adding NH4N03 and crystallising in vacuo the double salt 2Ce(N03)4. 4NH4N03.3H,0 is obtained. Dissolves in warm HClAq with evolution of CI and formation of CeXLj. Dis- solves easily in dilute acids in presence of re- ducing agents, e.g. alcohol, SO,Aq, ifec. Cerium teioxide. CeO;). (Cerium peroxide.) Said to be obtained as a reddish pp. by adding a slight excess of NH3Aq to Ce,3SO,Aq, and di- gesting with hydrogen peroxide (de Boisbaudran, C. R. 100, 605 ; Cleve, Bl. [2] 43, 53). Other oxides of cerium are described by Popp (A. 131, 361); Hermann (J. pr. 30, 184 ; 82, 385 ; 92, 113); the formula; Ce,09 and Ce„Or> are assigned to these oxides, respectively; but experiments made by Rammelsberg (P. 108, 40) and others tend to show that the only oxides which have been isolated are Ce,03, CeO,, and Ce03. Cerium, oxychlorides of, v. under Cerium, HALOID AND OXYHALOID COMPOUNDS OF.$