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).
Zeit., 1892, 16, p. 335) separate rubidium and caesium from the other alkali metals by converting them into double chlorides with stannic chloride; whilst J.
The platino-chlorides are reduced by hydrogen, and the caesium and rubidium chlorides extracted by water.
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.
Bunsen, the best source of rubidium and caesium salts is the residue left after extraction of lithium salts from lepidolite.
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.
Lithium, sodium, potassium, rubidium and caesium, and of the alkaline earth metals, viz.
This residue consists of sodium, potassium and lithium chlorides, with small quantities of caesium and rubidium chlorides.
The rubidium salts are generally colourless, mostly soluble in water and isomorphous with the corresponding potassium salts.
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.