atomic See also:

• WEIGHT

weight 85.45 See also:

• atomic weight 85.45 RUBIDIUM [symbol Rb (0=16)]

RUBIDIUM [See also:

• SYMBOL (Gr. o-uµ(3oXov, a sign)

symbol Rb (0=16)]  , a metallic See also:

• ELEMENT (Lat. elementum)

element belonging to the See also:

• GROUP

group of the See also:

• ALKALI

alkali metals . It is found in the minerals See also:

• LEPIDOLITE

lepidolite, See also:

• PETALITE

petalite and in various specimens of See also:

• MICA

mica and of carnallite, and in some See also:

• MINERAL

mineral See also:

• WATERS, TERRITORIAL

waters . It also occurs in See also:

• TEA (Chinese cha, Amoy dialect t€)

tea, See also:

• COCOA

cocoa, See also:

• COFFEE (Fr: cafe, Ger. Kaffee)

coffee, See also:

• TOBACCO

tobacco and in the ashes of beetroot . It was discovered by R . See also:

• BUNSEN, CHRISTIAN CHARLES JOSIAS, BARON VON (1791-186o,)
• BUNSEN, ROBERT WILHELM VON (1811-1899)

Bunsen and See also:

• KIRCHHOFF, GUSTAV ROBERT (1824-1887)
• KIRCHHOFF, JOHANN WILHELM ADOLF (1826-1908)

Kirchhoff (See also:

• ANN

Ann., 186o, 113, p . 337), in the spectroscopic examination of the residues obtained on evaporation of See also:

• WATER

water from a mineral See also:

• SPRING (from " to spring," " to leap or jump up," " burst out," O. Eng., springau, a common Teut. word, cf. Ger. springer, possibly allied to Gr. QnrFpxecOac, to move rapidly)

spring at See also:

• DURKHEIM

Durkheim, being characterized by two distinctive red lines . The best source of See also:

• RUBIDIUM [symbol Rb, atomic weight 85.45 (0=16)]

rubidium salts is the See also:

• RESIDUE (through the French, from the Lat. residuum, a remainder, from residere, to remain)

residue See also:

• LEFT

left after extracting See also:

• LITHIUM [symbol Li, atomic weight 7•oo (0=16)]

lithium salts from lepidolite, the method of separation being based on the different solubilities of the plating-chlorides of See also:

• POTASSIUM [symbol K (from kalium), atomic weight 39.114 0=16)]

potassium, rubidium and See also:

• CAESIUM (symbol Cs, atomic weight 132.9)

caesium in water (R . Bunsen, Ann., 1862, 122, p . 351) . A somewhat similar See also:

• PROCESS

process based on the varying solubilities of the corresponding alums has also been devised by Redtenbacher (Jour. prak . Chem., 1865, 95, P . 148) .

The See also:

• METAL
• METAL (through Fr. from Lat. metallum, mine, quarry, adapted from Gr. µATaXAov, in the same sense, probably connected with ,ueraAAdv, to search after, explore, µeTa, after, aAAos, other)

metal is prepared by distilling the carbonate with See also:

• CARBON (symbol C, atomic weight 12)

carbon (an explosive See also:

• COMPOUND
• COMPOUND (from Lat. componere, to combine or put together)

compound similar to that obtained from potassium and carbon monoxide is liable to be formed simultaneously); by reducing the hydroxide with See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

aluminium: 4RbOH+2AI=Rb2O Al203+ 2Rb + 2H2 (N . Beketoff, Ber., 1888, 21, p . 424 ref.); by reducing the carbonate (C . Winckler, Ber., 189o, 23, p . 51) or the hydroxide with See also:

• MAGNESIUM [symbol Mg, atomic weight 24.32 (0 = 16)]

magnesium (H . See also:

• ERDMANN
• ERDMANN, JOHANN EDUARD (1805-1892)

Erdmann and P . Kothner, Ann., 1899, 294, p . 55) ; and by See also:

• HEATING

heating the fused chloride with See also:

• CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

calcium in an exhausted See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

glass See also:

• TUBE (Lat. tuba)

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 See also:

• NICKEL
• NICKEL (symbol Ni, atomic weight 58.68 (0=16))

nickel See also:

• VESSEL (O. Fr. vaissel, from a rare Lat. vascellum, dim. of vas, vase, urn)

vessel, with an See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron See also:

• WIRE (A.S. wir, a wire; cf. Swed. vire, to twist, M.H.G. wiere, a gold ornament, Lat. viriae, armlets, ultimately from the root wi, to twist, bind)

wire See also:

• CATHODE

cathode and iron See also:

• CYLINDER (Gr. KvAwSpos, from KvXivaety, to roll)

cylinder anode; the product on cooling being opened under See also:

• PYRIDINE

pyridine cooled by a freezing mixture (G. von Hevesy, Zeit. anorg .

Chem., 1910, 67, p . 242) . It is a silvery See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white metal which melts at 38.5° C. and has a specific gravity of 1.52 . It oxidizes rapidly on exposure to See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air, and decomposes See also:

• COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

cold water very rapidly . It closely resembles caesium and potassium in its See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

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 See also:

• FORM (Lat. forma)

form of colourless needles by H . See also:

• MOISSAN, HENRI (1852-1907)

Moissan (Comptes rendus, 1903, 136, p . 587) from the See also:

• DIRECT

direct See also:

• COMBINATION (Lat. combinare, to combine)

combination of its constituent elements . It rapidly dissociates when heated in vacuo to 300° C . The existence of the See also:

• OXIDE

oxide Rb2O appears to be doubtful, the results of Erdmann and Kiithner (loc. cit.) pointing to the formation of RbO2 by the direct See also:

• UNION
• UNION (known locally as Union Hill and officially as Town of Union)

union of the metal with dry See also:

• OXYGEN (symbol 0, atomic weight 16)

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 See also:

• DISTILLATION (from the Lat. distillare, more correctly destillare, to drop or trickle down)

distillation in vacuo, has obtained oxides of See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition Rb202 (yellowish white), Rb203 (See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black) and Rb204 (yellow) . Rubidium hydroxide, RbOH, is a colourless solid which is formed by the See also:

• ACTION

action of rubidium on water, or by the addition of baryta water to a See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution of rubidium sulphate . It is readily soluble in water, the solution being very alkaline and See also:

• CAUSTIC (Gr. rcavvraubs, burning)

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, RbCI, is formed on burning rubidium in See also:

• CHLORINE (symbol Cl, atomic weight 35`46 (0=16)

chlorine, or on dissolving the hydroxide in aqueous hydrochloric See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

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 See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double salts . It combines also with See also:

• IODINE (symbol I, atomic weight '26.92)

iodine chloride and bromide and with See also:

• BROMINE (symbol Br, atomic weight 79-96)

bromine chloride and with bromine (H . L .

See also:

• WELLS
• WELLS, CHARLES JEREMIAH (1798?–1879)
• WELLS, DAVID AMES (1828—1898)
• WELLS, HERBERT GEORGE (1866— )
• WELLS, SIR THOMAS SPENCER, 1ST BART

Wells and H . L . See also:

• WHEELER, JOSEPH (1836-1906)
• WHEELER, WILLIAM ALMON (1819-1887)

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 See also:

• MILK (0. Eng. meoluc; from a common Indo-European root, cf. Lat. mulgere, Gr. ?t dXyetv)

milk of See also:

• LIME
• LIME (O. Eng. lim, Lat. limes, mud, from linere, to smear)

lime on rubidium See also:

• ALUM

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-Di rfurt (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 See also:

• SULPHUR

sulphur is transformed into the yellow tetrasulphide, Rb2S4.2H2O . A pentasulphide, Rb2S3, which crystallizes in red prisms melting at 223° C., 1s also obtained by the direct union of the normal sulphide with sulphur . When heated in a current of See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen it is transformed into the colourless disulphide, whilst if the heating be carried out in a current of See also:

• NITROGEN [symbol N., atomic weight 14.01, 0=16]

nitrogen it yields the trisulphide, Rb2S,.See also:

• H2O (combined)

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 See also:

• AMMONIA (NH3)

ammonia on rubidium . The product combines with See also:

• ACETYLENE

acetylene to form rubidium acetylide acetylene, Rb2C2•C2H2, which on heating in vacuo loses acetylene and leaves a residue of rubidium See also:

• CARBIDE

carbide Rb2C2 (ibid. p . 1217) . Rubidium carbonate, Rb2CO3, formed by the addition of ammonium carbonate to rubidium hydroxide, is a crystalline See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass which melts in its water of See also:

• CRYSTALLIZATION

crystallization when heated . The atomic See also:

• WEIGHT

weight of rubidium was determined by R .

Bunsen (Pogg . Ann., 1861, 113, p . 339), See also:

• PICARD, LOUIS JOSEPH ERNEST (1821-1877)

Picard (Zeit. anal . Chem., 1862, 1, p 519) and Godeffroy (Ann., 1876, 181, p . 185), the methods being E . on the See also:

• CONVERSION (Lat. conversio, from convertere, to turn or ,change)

conversion of rubidium halides into the corresponding See also:

• SILVER

silver See also:

• SALT (a common Teutonic word, cf. Dutch zout, Ger. Salz, Scand. salt; cognate with Gr. &Xs, Lat. sal)
• SALT, SIR TITUS, BART

salt, and the values obtained vary from 85.4o to 85.5o . Thedetermination of E . H . See also:

• ARCHIBALD, 5TH EARL OF DOUGLAS (c. 1391–1439)

Archibald (Jour . Chem . See also:

• SOC

Soc., 1904, 85, p . 776) from the See also:

• ANALYSIS (Gr. avci and Meta, to break up into parts)

analysis of the chloride and bromide gives the mean value as 85.485 (0 =16) .