noun
definition
The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal.
Examples of caesium in a Sentence
The separation of caesium from the minerals which contain it is an exceedingly difficult and laborious process.
Caesium compounds can be readily recognized by the two bright.
Within two years of the invention the authors announced the discovery of two metals, rubidium and caesium, closely allied to sodium, potassium and lithium in properties, in the mineral lepidolite and in the Diirkheim mineral water.
Rubidium, caesium, thallium, indium and gallium were first discovered by means of this instrument; the study of the rare earths is greatly facilitated, and the composition of the heavenly bodies alone determinable by it.
They are silicates, usually orthosilicates, of aluminium together with alkalis (potassium, sodium, lithium, rarely rubidium and caesium), basic hydrogen, and, in some species magnesium, ferrous and ferric iron, rarely chromium, manganese and barium.
It combines with alkaline chlorides - potassium, rubidium and caesium - to form crystalline plumbichlorides; it also forms a crystalline compound with quinoline.
The solubility of the various alums in water varies greatly, sodium alum being readily soluble in water, whilst caesium and rubidium alums are only sparingly soluble.
Titanium sesquisulphate, T12(S04)3.8H20, obtained by concentrating the violet solution formed when the metal is dissolved in sulphuric acid, is interesting since it forms a caesium alum, CsTi(S04)2.12H20.
In modern chemistry alkali is a general term used for compounds which have the property of neutralizing acids, and is applied more particularly to the highly soluble hydrates of sodium and potassium and of the three rarer "alkali metals," caesium, rubidium and lithium, also to aqueous ammonia.
Bunsen, the best source of rubidium and caesium salts is the residue left after extraction of lithium salts from lepidolite.
This residue consists of sodium, potassium and lithium chlorides, with small quantities of caesium and rubidium chlorides.
The platino-chlorides are reduced by hydrogen, and the caesium and rubidium chlorides extracted by water.
In order to separate caesium from rubidium, use is made of the different solubilities of their various salts.
Hackspill (Comptes Rendus, 5905, 141, p. 101) finds that metallic caesium can be obtained more readily by heating the chloride with metallic calcium.
The atomic weight of caesium has been determined by the analysis of its chloride and bromide.
Caesium hydroxide, Cs(OH) 2, obtained by the decomposition of the sulphate with baryta water,is a greyish-white deliquescent solid,which melts at a red heat and absorbs carbon dioxide rapidly.
CsCl, is obtained by the direct action of chlorine on caesium, or by solution of the hydroxide in hydrochloric acid.
Caesium sulphate, Cs 2 SO 4, may be prepared by dissolving the hydroxide or carbonate in sulphuric acid.
Caesium nitrate, CsNO 3, is obtained by dissolving the carbonate in nitric acid, and crystallizes in glittering prisms, which melt readily, and on heating evolve oxygen and leave a residue of caesium nitrite.
Matthiessen, sodium ranks fourth to silver, copper and gold as a conductor of electricity and heat, and according to Bunsen it is the most electropositive metal with the exception of caesium, rubidium and potassium.
The chlorine is not completely precipitated by silver nitrate in nitric acid solution, the ionization apparently not proceeding to all the chlorine atoms. Thallic iodide, T11 3, is interesting on account of its isomorphism with rubidium and caesium tri-iodides, a resemblance which suggests the formula T11 (12) for the salt, in which the metal is obviously monovalent.
It closely resembles caesium and potassium in its general properties.
These sulphides are much less hygroscopic than the corresponding caesium compounds.
Tutton's investigations of the morphotropic effects of the metals potassium, rubidium and caesium, in combination with the acid radicals of sulphuric and selenic acids, showed that the replacement of potassium by rubidium, and this metal in turn by caesium,was accompanied by progressive changes in both physical and crystallographical properties, such that the rubidium salt was always intermediate between the salts of potassium and caesium (see table; the space unit is taken as a pseudo-hexagonal prism).