atomic See also:

• WEIGHT

weight 181•o See also:

• atomic weight 181•o TANTALUM [symbol Ta (0=16)]

TANTALUM [See also:

• SYMBOL (Gr. o-uµ(3oXov, a sign)

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

• ELEMENT (Lat. elementum)

element, sparingly distributed in nature and then almost invariably associated with See also:

• COLUMBIUM, or NIOBIUM (symbol Cb or Nb, atomic weight 94)

columbium . Its See also:

• HISTORY

history is intermixed with that of columbium . In 18o1 C . Hatchett detected a new element, which he named columbium, in a See also:

• MINERAL

mineral from See also:

• MASSACHUSETTS (an Indian name, originally applied to a tribe of Indians)

Massachusetts, and in 1802 A . G . Ekeberg discovered an element, See also:

• TANTALUM [symbol Ta, atomic weight 181•o (0=16)]

tantalum, in some See also:

• SWEDISH

Swedish See also:

• YTTRIUM [symbol, Y; atomic weight, 89.0 (0 =16)]

yttrium minerals . In 1809 W . H . See also:

• WOLLASTON, WILLIAM (1659--1724)
• WOLLASTON, WILLIAM HYDE (1766-1828)

Wollaston unsuccessfully endeavoured to show that columbium and tantalum were identical . In 1844 H . See also:

• ROSE
• ROSE (Rosa)
• ROSE, GEORGE (1744-1818)
• ROSE, HUGH JAMES (1795—1838)
• ROSE, WILLIAM STEWART (1775-1843)

Rose detected two new elements in the columbites of the Bodenmais, which he named niobium and pelopium; dianium was discovered by W . X .

F. von See also:

• KOBELL, WOLFGANG XAVER FRANZ, BARON VON (1803-1882)

Kobell in various columbites; and ilmenium and neptunium were discovered by R . See also:

• HERMANN, JOHANN GOTTFRIED JAKOB (1772–1848)
• HERMANN, KARL FRIEDRICH (1804–1855)

Hermann . The researches of C . W . Blomstrand, and others, especially of See also:

• MARIGNAC, JEAN CHARLES GALISSARD DE (1817-1894)

Marignac, proved the identity of columbium, dianium and niobium, and that ilmenium was a mixture of columbium and tantalum . It is very probable that neptunium is a similar mixture . See also:

• BERZELIUS, JONS JAKOB (1779-1848)

Berzelius, who prepared tantalic See also:

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

acid from the mineral tantalite in 1820, obtained an impure 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 by See also:

• HEATING

heating See also:

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

potassium tantalofluoride with potassium . In 1902 H . See also:

• MOISSAN, HENRI (1852-1907)

Moissan obtained a See also:

• CARBON (symbol C, atomic weight 12)

carbon-bearing metal by fusing the pentoxide with carbon in the electric See also:

• FURNACE

furnace . The preparation of the pure metal was successfully effected by See also:

• WERNER, ABRAHAM GOTTLOB (1750-1817)
• WERNER, ANTON ALEXANDER VON (1843– )
• WERNER, FRIEDRICH LUDWIG ZACHARIAS (1768–1823)

Werner von See also:

• BOLTON (BOLTON-LE-MOORS)
• BOLTON (or BOULTON), EDMUND (1S75?-1633?)
• BOLTON, DUKES OF

Bolton in 1905, who fused the compressed product obtained in the Berzelius See also:

• PROCESS

process in the electric furnace, See also:

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

air being excluded . An alternative method consisted in passing an electric current through a filament of the tetroxide in a vacuum . The metal is manufactured, for use as filaments in electric lamps, by the See also:

• ACTION

action of See also:

• SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium on sodium tantalofluoride .

The pure metal is See also:

• SILVER

silver-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 in See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour, is very ductile, and becomes remarkably hard when hammered, a See also:

• DIAMOND

diamond See also:

• DRILL

drill making little impression upon it . Its tensile strength is higher than that of See also:

• STEEL, FLORA ANNIE (1847– )

steel . It melts between 2250° and 2300°, its specific See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat is 0.0365, coefficient of expansion 0•0000079, and specific gravity 16.64 . When heated in air the metal See also:

• BURNS, JOHN (1858– )
• BURNS, ROBERT (1759-1796)
• BURNS, SIR GEORGE

burns if in the See also:

• FORM (Lat. forma)

form of thin 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, and is superficially oxidized if more compact . At a red heat it absorbs large volumes of See also:

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

hydrogen and See also:

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

nitrogen, the last traces of which can only be removed by See also:

• FUSION

fusion in the electric furnace . These substances, and also carbon, See also:

• SULPHUR

sulphur, See also:

• SELENIUM [symbol Se, atomic weight 79.2 (O=16)]

selenium and See also:

• TELLURIUM [Symbol Te, atomic weight 127.5 (0=16)]

tellurium, render the metal very brittle . Tantalum is not affected by alkaline solutions, but is disintegrated when fused with potash . Hydrofluoric acid is the only acid which attacks it . It See also:

• ALLOYS (through the Fr. aloyer, from Lat. alligare, to combine)

alloys with See also:

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

iron, See also:

• MOLYBDENUM [symbol, Mo; atomic weight, 96 (0=16)]

molybdenum and See also:

• TUNGSTEN [symbol W, atomic weight 184.o (0=16)]

tungsten, but not with silver or See also:

• MERCURY
• MERCURY (MERCU1uus)
• MERCURY (symbol Hg, atomic weight = 2oo)

mercury . In its chemical relationships tantalum is associated with See also:

• VANADIUM

vanadium, columbium and See also:

• DIDYMIUM (from the Gr. &Segos, twin)

didymium in a sub-See also:

• GROUP

group of the periodic See also:

• CLASSIFICATION (Lat. classis, a class, probably from the root cal-, cla-, as in Gr. icaMce, clamor)

classification . In See also:

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

general it is pentavalent, but divalent compounds are known . Tantalum tetroxide, Ta204, is a porous dark See also:

• GREY, CHARLES GREY, 2ND EARL (1764-1845)
• GREY, HENRY GREY, 3RD EARL (1802-1894)
• GREY, LADY JANE (1537-1554)
• GREY, SIR EDWARD
• GREY, SIR GEORGE (1812–1898)

grey See also:

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

mass harder than 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, and is obtained by reducing the pentoxide with See also:

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

magnesium .

It is unaffected by any acid or mixture of acids, but burns to the pentoxide when heated . Tantalum pentoxide, Ta2O6, is a white amorphous infusible See also:

• POWDER (through O. Fr. puldre, modern poudre, from Lat. pulvis, pulveris, dust)

powder, or it may be crystallized by strongly heating, or by fusing with See also:

• BORON (symbol B, atomic weight I I)

boron trioxide or microcosmic 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 . It is insoluble in all acids . It is obtained from potassitn tantalofluoride by heating with sulphuric acid to 400°, boiling out with See also:

• WATER

water, and decomposing the residual See also:

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

compound of the See also:

• OXIDE

oxide and sulphuric acid by ignition, preferably with the addition of ammonium carbonate . Tantalic acid, HTaO3, is a gelatinous mass obtained by mixing the chloride with water . It gives rise to salts, termed the tantalates . The normal salts are all insoluble in water; the complex acid, hexatantalic acid, I-IBTa6Ots (which does not exist in the See also:

• FREE

free See also:

• STATE
• STATE, GREAT OFFICERS OF

state), forms soluble salts with the alkaline metals . Pertantalic acid, HTaO4, is obtained in the hydrated form as a white precipitate by adding sulphuric acid to potassium pertantalate, K2TaO2 . 1H20, which is formed when hydrogen peroxide is added to a See also:

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

solution of potassium hexatantalate . Tantalum penta, uoride, TaF5, for a See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time only known in solution, may he obtained by passing See also:

• FLUORINE (symbol F, atomic weight 19)

fluorine over an alloy of tantalum and See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

aluminium, and purifying by See also:

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

distillation in a vacuum . It forms colourless, very hygroscopic prisms, which attack glass, slowly at See also:

• ORDINARY (med. Lat. ordinarius, Fr. ordinaire)

ordinary temperatures, more rapidly when heated (Ber., 1909, 42, p . 492) .

Its 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 with the alkaline fluorides are very important, and serve for the separation of the metal from columbium and See also:

• TITANIUM [symbol Ti, atomic weight 48.1 (0 = 16)]

titanium . Tantalum pentachloride, TaC16, is obtained as See also:

• LIGHT

light yellow needles by heating a mixture of the pent-oxide and carbon in a current of See also:

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

chlorine . By heating with sodium See also:

• AMALGAM

amalgam and separating with hydrochloric acid, the dichloride, TaCIi•2H20, is obtained as See also:

• EMERALD

emerald See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green hexagonal crystals . The pentabroniide exists, but tantalum and See also:

• IODINE (symbol I, atomic weight '26.92)

iodine apparently donot combine . Tantalum forms a sulphide, TaS2, and two nitrides, TaN2 and Ta3N5, have been described . Marignac determined the atomic See also:

• WEIGHT

weight to be 181, but Henrichsen and N . Sahlbom (Ber., 1906, 39, p . 2600) obtained 179.8 (H =I) by converting the metal into pentoxide at a dull red heat .