in water (R. Bunsen, Ann., 1862, 122, p. 351). A somewhat similar process based on the varying solubilities of the corresponding alums has also been devised by Redtenbacher (Jour. prak. Chem., 1865, 95, p. 148). The metal is prepared by distilling the carbonate with carbon (an explosive compound similar to that obtained from potassium and carbon monoxide is liable to be formed simultaneously); by reducing the hydroxide with aluminium: 4RbOH+2Al=Rb2O Al2O3+2Rb+2H2 (N. Beketoff, Ber., 1888, 21, p. 424 ref.); by reducing the carbonate (C. Winckler, Bef., 1890, 23, p. 51) or the hydroxide with magnesium (H. Erdmann and P. Köthner, Ann., 1899, 294, p. 55); and by heating the fused chloride with calcium in an exhausted glass tube at 400–500° C. (L. Hackspill, Comptes rendus, 1905, 141, p. 101). The metal was first obtained electrolytically in 1910 by electrolysing the fused hydroxide in a nickel vessel, with an iron wire cathode and iron cylinder anode; the product on cooling being opened under pyridine cooled by a freezing mixture (G. von Hevesy, Zeit. anorg. Chem., 1910, 67, p. 242). It is a silvery white metal which melts at 38⋅5° C. and has a specific gravity of 1⋅52. It oxidizes rapidly on exposure to air, and decomposes cold water very rapidly. It closely resembles caesium and potassium in its general properties. The rubidium salts are generally colourless, mostly soluble in water and isomorphous with the corresponding potassium salts.
Rubidium hydride, RbH, was obtained in the form of colourless needles by H. Moissan (Comptes rendus, 1903, 136, p. 587) from the direct combination of its constituent elements. It rapidly dissociates when heated in vacuo to 300° C. The existence of the oxide Rb2O appears to be doubtful, the results of Erdmann and Köthner (loc. cit.) pointing to the formation of RbO2 by the direct union of the metal with dry oxygen. E. Rengade (Comptes rendus, 1907, 144, p. 920), by partially oxidizing the metal in a current of dry oxygen and removing excess of metal by distillation in vacuo, has obtained oxides of composition Rb2O2 (yellowish white), Rb2O3 (black) and Rb2O4 (yellow). Rubidium hydroxide, RbOH, is a colourless solid which is formed by the action of rubidium on water, or by the addition of baryta water to a solution of rubidium sulphate. It is readily soluble in water, the solution being very alkaline and caustic. It melts at 301°. Evaporation of the aqueous solution at 15° C. deposits a crystalline hydrated hydroxide of composition RbOH⋅2H2O (R. de Forcrand, Comptes rendus, 1909, 149, p. 1341). Rubidium chloride, RbCl, is formed on burning rubidium in chlorine, or on dissolving the hydroxide in aqueous hydrochloric acid. It crystallizes in colourless cubes and volatilizes when heated very strongly. It is soluble in water and combines with many metallic chlorides to form double salts. It combines also with iodine chloride and bromide and with bromine chloride and with bromine (H. L. Wells and H. L. Wheeler, Amer. Jour. Sci., 1891 (3), 43, p. 475).
Rubidium sulphate, Rb2SO4, is formed by the action of sulphuric acid on the carbonate or hydroxide of the metal, or by the action of milk of lime on rubidium alum, the excess of lime being precipitated by rubidium carbonate and the solution neutralized by sulphuric acid. It forms large colourless hexagonal crystals. Several sulphides of the metal have been described by W. Biltz and E. Wilke-Dörfurt (Zeit. anorg. Chem., 1906, 48, p. 297). The normal sulphide, Rb2S⋅4H2O, is colourless, and when heated in aqueous solution with the requisite amount of sulphur is transformed into the yellow tetra sulphide, Rb2S4⋅2H2O. A pentasulphide, Rb2S5, which crystallizes in red prisms melting at 223° C., is also obtained by the direct union of the normal sulphide with sulphur. When heated in a current of hydrogen it is transformed into the colourless disulphide, whilst if the heating be carried out in a current of nitrogen it yields the trisulphide, Rb2S3⋅H2O. These sulphides are much less hygroscopic than the corresponding caesium compounds. Rubidium nitrate, RbNO3. obtained by the action of nitric acid on the carbonate, crystallizes in needles or prisms and when strongly heated is transformed into a mixture of nitrite and oxide. Rubidium ammonium, RbNH3, was prepared by H. Moissan (Comptes rendus, 1903, 136, p. 1177) by the action of liquid ammonia on rubidium. The product combines with acetylene to form rubidium acetylide acetylene, Rb2C2⋅C2H2, which on heating in vacuo loses acetylene and leaves a residue of rubidium carbide Rb2C2 (ibid. p. 1217). Rubidium carbonate, Rb2CO3, formed by the addition of ammonium carbonate to rubidium hydroxide, is a crystalline mass which melts in its water of crystallization when heated.
The atomic weight of rubidium was determined by R. Bunsen (Pogg. Ann., 1861, 113, p. 339), Picard (Zeit. anal. Chem., 1862, 1, p. 519) and Godeffroy (Ann., 1876, 181, p. 185), the methods being a on the conversion of rubidium halides into the corresponding silver salt, and the values obtained vary from 85⋅40 to 85⋅50. The determination of E. H. Archibald (Jour. Chem. Soc., 1904, 85, p. 776) from the analysis of the chloride and bromide gives the mean value as 85⋅485 (O=16).
RUBINSTEIN, ANTON GRIGOROVICH (1829–1894),
Russian pianist, borri of Jewish parentage on the 28th of
November 1829 at Wechwotynetz, in Podolia, was the son of
a pencil manufacturer who migrated to Moscow. The Rubinstein
family, at the dictate of Anton’s grandfather Roman
Rubinstein, Thad all been baptized at the time of the ukase
against the Jews issued in 1830 by the Tsar Nicholas. Anton
was then one year old. Besides his mother he had but one
teacher, the piano master Alexander Villoing, of whom he
declared at the end of his own career that he had never met a
better. In July 1838 Rubinstein appeared in the theatre of
the Petrowski Park at Moscow; and in the year following he
went to Paris after Villoing, and in 1840 played before Liszt.
For some time after this Rubinstein travelled in Holland,
Germany and Scandinavia, and reached England in 1842,
where on the 20th of May he made his first appearance at a
Choral Fund concert. In 1845, after a brief visit to Moscow
in 1843, he went with his family (including his brother Nikolaus)
to Berlin in order to complete his musical education. Dehn
was their master, and Mendelssohn, whom Rubinstein had
met previously in London, their best friend. The sudden
death of Rubinstein’s father necessitated the withdrawal of
his mother and Nikolaus to Moscow, while Anton, on Dehn’s
advice, went to Vienna to seek a livelihood. Hence, after
more hard study for nearly two years, he went with the flautist
Heindl, and later alone, on a concert tour in Hungary; and
the outbreak of the revolution in Vienna preventing his return
there, he went via Berlin to St Petersburg, where the Grand
Duchess Hélène appointed him Kammervirtuos. About this
time an unfortunate error of the police nearly caused his expatriation
to Siberia, from which he was saved by his patroness.
During the next eight years Rubinstein spent most of his time
in St Petersburg studying, playing and composing. His
opera Dmitri Donskoi was produced there in 1851, and Toms
der Narr in 1853. Die Sibirischen Jäger, written about the
same time, was not produced. On the advice of his patroness
and Count Wilhorski he visited Hamburg and Leipzig, and
arrived for the second time in London in 1857, when at a
Philharmonic concert he introduced his own concerto in G.
In the following year he was in London again, having in the
meantime been appointed Concert Director of the Royal
Russian Musical Society. In 1862, in collaboration with Carl
Schuberth, he founded the St Petersburg Conservatorium, of
which he was director until 1867. In 1868 he travelled in
Germany, France and England, and remained for some time
in Vienna, where he introduced a large number of his own
compositions. Thence he went to America in 1872 and 1873,
when he returned to Russia, and after a short rest set off once
more on concert tours. In this manner the rest of his life
was spent, until in 1885 he began a series of historical recitals
of immense interest, which he gave in most of the chief European
capitals. He died on the 20th of November 1894.
In addition to the works already named, Rubinstein left compositions in almost every known form. Among other of his operas are Die Kinder der Haide, Feramors (Lalla Roukh), Nero, Der Dämon and Die Makkabäer, this last perhaps more frequently played than all the others, of which the chief defect is their lack of dramatic point. On the subject of oratorio Rubinstein held original views, though his attempt to realize them in Moses and Christus was not completely successful, while his efforts in Berlin and London to found a Sacred Theatre failed entirely. Nevertheless he himself regarded the Christus as his greatest achievement. The most familiar of his five symphonies are the “Ocean” and the “Dramatic.” He wrote scores on scores of pianoforte works, from complex concertos to the most commonplace salonstücke; abundance of concerted chamber-music, and a number of songs and duets. which enjoyed some popularity. He also published several books, including his Reminiscences and Die geistliche Oper.
