Online Encyclopedia

atomic weight 48.1 TITANIUM [symbol T...

Online Encyclopedia
Originally appearing in Volume V26, Page 1018 of the 1911 Encyclopedia Britannica.
Spread the word: del.icio.us del.icio.us it!

atomic

See also:
weight 48.1 TITANIUM [symbol Ti (0 = 16)]  , a metallic chemical element . Its
See also:
discovery as an element was due to William Gregor in 1789 who found in the
See also:
mineral
See also:
ilmenite or menachinite a new earth, which was regarded as the
See also:
oxide of a new metal, menachin . Independently of him Klaproth in 1793 discovered a new metal in
See also:
rutile, and called it titanium; he subsequently found that it was identical with Gregor's element . Klaproth, however, was unable to prepare the pure oxide, which was first accomplished in 1821 by Rose . The
See also:
isolation of the pure metal is of much later date . Titanium, although
See also:
pretty widely diffused throughout the mineral
See also:
kingdom, is not found in abundance . The commonest titanium mineral is rutile or titanium dioxide, TiO2;
See also:
anatase and
See also:
brookite are crystalline allotropes . Titanium is most frequently found associated with iron; ilmenite (Ger . Titan-eisen) is FeTiO3, perofskite (Ca,Fe)TiO3, and the metal occurs in most magnetic iron ores . The titanates are well marked in the mineral king-dom . Ilmenite is isomorphous with geikielite, MgTiO3, and pyrophanite, MnTiO3; many of the " rare minerals "—aeschynite, euxenite, polycrase, &c.—contain titanates (and also niobates) . Silicates also occur;
See also:
sphene or titanite, CaTiSiO5, is the commonest; keilhauite is rarer .

The isolation of metallic titanium is very difficult since it readily combines with

nitrogen (thus resembling boron and magnesium) and carbon . In 1822 Wollaston examined a specimen of those beautiful copper-like crystals which are occasionally met with in iron-
See also:
furnace slags, and declared them to be metallic titanium . This view had currency until 1849, when Wohler showed that the crystals are a compound, Ti(CN)2.3Ti3N2, of a
See also:
cyanide and a nitride of the metal . An impure titanium was made by Wohler and Sainte-Claire Deville in 1857 by
See also:
heating to redness fluotitanate of potassium (see below) in the vapour of sodium in an atmosphere of dry hydrogen, and extracting the alkaline fluoride formed by
See also:
water . The metal thus produced formed a dark brown amorphous powder resembling iron as obtained by the reduction of its oxide in hydrogen . In 1887 Nilson and Petersson (Zeit. phys . Chem . 1, p . 25) obtained a purer product by heating the chloride with sodium in a steel cylinder; it then formed yellow scales with a bluish
See also:
surface colour . H . Moissan (Comet. rend., 1895, 120, p . 290) obtained a still purer metal by igniting the oxide with carbon in the electric furnace .

The product has a brilliant

white fracture, a specific gravity of 4.87, very friable, but harder than
See also:
quartz or steel . Moissan (ibid., 1906, 142, p . 673) has distilled this metal in a very intense electric furnace . When heated in air it burns brilliantly with the formation of the oxide . It combines directly with the
See also:
halogens, and dissolves in cold dilute sulphuric acid, in hot strong hydrochloric acid and in aqua regia, but less readily in nitric acid . Its most curious
See also:
property is the readiness with which it unites with nitrogen . Several nitrides have been de-scribed . Ti3N4 is a copper-coloured powder obtained by heating the ammonio-chloride TiC13.4NH3 in
See also:
ammonia . TiN2 is a dark blue powder obtained when the oxide is ignited in an atmosphere of ammonia; while TiN is obtained as a
See also:
bronze yellow mass as hard as the
See also:
diamond by heating the oxide ih an atmosphere of nitrogen in the electric furnace . In its chemical relations, titanium is generally tetravalent, and occurs in the same sub-
See also:
group of the periodic classification as
See also:
zirconium, cerium and thorium . It forms several oxides, TiO2, Ti203 and TiO3 being the best known; others (some of doubtful existence) have been described from time to time . Titanium iioxide, TiO2, occurs in nature as the three distinct mineral
See also:
species rutile, brookite and anatase .

Rutile assumes tetragonal forms isomorphous with cassiterite, SnO2 (and also

See also:
zircon, ZrSiO4) ; anatase is also tetragonal, and brookite or thorhombic . Rutile is the most
See also:
stable and anatase the least, a character reflected in the decrease in density from rutile (4.2) and brookite (4.0) to anatase (3.9) . The minerals are generally found together—a feature rarely met with in the case of polymorphs . They have been obtained artificially by Hautefeuille by the interaction of titanium fluoride and steam . At a red heat rutile is produced, at the boiling point of
See also:
zinc brookite, and of cadmium anatase . It is apparent that these minerals all result in nature from pneumatolytic
See also:
action . Amorphous titanium oxide may be obtained in a pure form by fusing the mineral, very finely powdered, with six times its
See also:
weight of potassium bisulphate in a platinum crucible, then extracting the melt with cold water and boiling the filtered solution for a long time . Titanic oxide separates out as a white
See also:
hydrate, which, however, is generally contaminated with ferric hydrate and often with tin oxide . A better method is Wohler's, in which the finely powdered mineral is fused with twice its weight of potassium carbonate in a platinum crucible, the melt powdered and treated in a platinum basin with aqueous hydrofluoric acid . The alkaline titanate first produced is converted into crystalline fluotitanate, K2TiF6, which is with difficulty soluble and is extracted with hot water and filtered off . The filtrate, which may be collected in glass vessels if an excess of hydrofluoric acid has been avoided, deposits the greater
See also:
part of the salt on cooling . The crystals are collected, washed, pressed and recrystallized, whereby the impurities are easily removed .

The pure salt is dissolved in hot water and decomposed with ammonia to produce a slightly ammoniacal hydrated oxide; this, when ignited in platinum, leaves pure TiO2 in the form of brownish lumps, the specific gravity of which varies from 3:9 to 4.25, according to the temperature at which it was kept in igniting . The more intense the heat the denser the product . The oxide is fusible only in the oxy-hydrogen

flame . It is insoluble in all acids, except in hot concentrated sulphuric, when finely powdered . If the sulphuric acid solution be evaporated to dryness the residue, after cooling, dissolves in cold water . The solution, if boiled, deposits its titanic oxide as a hydrate called
See also:
meta-titanic acid, TiO(OH)2, because it differs in its properties from orthotitanic acid, Ti(OH)4, obtained by decomposing a solution of the chloride in cold water with alkalis . The ortho-
See also:
body dissolves in cold dilute acids; the meta-body does not . If titanic oxide be fused with excess of alkaline carbonate a titanate, R2TiO3, is formed . This salt is decomposed by -water with the formation of a solution of
See also:
alkali
See also:
free of titanium, and a residue of an acid titanate, which is insoluble in water but soluble in cold aqueous mineral acids . The titanates are very similar to the silicates in their tendency to assume complex forms, e.g. the potassium salts are K2TiO2.4H2O, K2Ti3Oi.3H2O and K2Ti6O13•2H2O . Titanium monoxide, TiO, is obtained as black prismatic crystals by heating the dioxide in the electric furnace, or with magnesium powder . Titanium sesquioxide, Ti2O3, is formed by heating the dioxide in hydrogen .

A hydrated form is prepared when a solution of titanic acid in hydrochloric acid is digested with copper, or when the trichloride is precipitated with alkalis . Titanium trioxide, TiOa, is obtained as a yellow precipitate by dropping the chloride into

See also:
alcohol, adding hydrogen peroxide, and finally ammonium carbonate or potash . When shaken with potash and air it undergoes autoxidation, hydrogen peroxide being formed first, which converts the trioxide into the dioxide and possibly pertitanic acid; this acid may contain sexavalent titanium (see W . Manchot and Richter, Ber., 1906, 39, pp . 320, 488, and also Faber, Abst . Journ . Chem .

End of Article: atomic weight 48.1 TITANIUM [symbol Ti (0 = 16)]
[back]
KALMAN [KOLOMAN] TISZA (1830-1902)
[next]
TITANOTHERIIDAE (also known as Menodontidae and Bro...

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click and select "copy." Paste it into a website, email, or other HTML document.