A Treatise on Chemistry by Henry Enfield Roscoe Carl Schorlemmer Harold Govett Colman Arthur Harden

Author:Henry Enfield Roscoe , Carl Schorlemmer , Harold Govett Colman , Arthur Harden
Language: eng
Format: epub
Publisher: Macmillan
Published: 1907-03-25T05:00:00+00:00

1 Crtll. Ann, 1791.

3 E 2

mainly of titanium dioxide, but he did not succeed in obtaining the oxide in the pure state, this having been first accomplished in 1821 by Rose.

Titanium is a comparatively rare element and is not foand in the metallic state. It occurs as the dioxide, TiO^, in thrve minerals, rutile, brookite, and anatase, which possess difierent crystalline forms, and also in combination with ferrous and ferric oxides in titanic iron ore or ilmenite, FeTiOgj and with lime and oxide of iron in perofskite, (Ca,Fe)Ti03, as well as in titanitc or sphene, CaTiSiO^; schorlomite, Ca(Ti,Fe)Si05, and keilhauite, CaY(Ti,Al,Fe)Si05. Magnetic iron oi-e also frequently contains larger or smaller quantities of titanium dioxide, and this titanium finds its way into many blast-furnace slags and pig-irons. Titanium occurs in small quantity in several other minerals, and traces have been found in trap and basalt, in many amphiboles and micas, and in garnet, and hence it occurs in most fertile soils, in many clays, and likewise in certain mineral waters. It has been found in human and ox flesh and bone/ and occurs in the ashes of all plants ^ and in many peats,' whilst its presence has been detected in certain meteorites, and it forms an important constituent of the solar atmosphere.

Preparation of Metallic Titanium. —It appears very doubtfiil whether metallic titanium has yet been obtained in the pure condition ; the usual methods for the reduction of the oxide, such as heating with metallic sodium and magnesium, yield products which still contain considerable quantities of titanium monoxide, and the product obtained by the action of sodium on halogen derivatives of titanium also usually contains small quantities of the monoxide, formed by the action of the moisture present, and of the nitride, obtained by the direct union of the metal with nitrogen, which it is almost impossible completely to exclude. Owing to the extreme readiness with which titanium and nitrogen combine at high temperatures, and the metallic appearance of the nitride, this compound was mistaken by the earlier investigators for the metal itself, as was also the compound which it forms with carbon and nitrogen, now known as titanium cyanonitride.

The nearest approach to the pure element has been obtained

1 Baakerville, /. Amer. Chem, Soc. 1899, 21, 1099.

2 W^ait, J. Amer. Chem. Soc. 1896,18,402 ; Lippmann, Ber. 1897, 80, 3037. » Baskerville, ./. Amer. Chcm. Soc. 1899, 21, 402.

by Moissan, who fused carbon with an excess of titanium dioxide

at a very high temperature in the electric furnace. Three

distinct layers are found in the solidified product, the uppermost

consisting of titanium containing about 5 per cent, of carbon,

the second of the nitride, and the third of titanium monoxide.

If the top layer be heated again with an excess of titanium

dioxide the quantity of carbon is reduced to 2 per cent., and

the product is free from nitrogen and silicon.^ Thus prepared

titanium has a brilliant white fracture' and is hai-d enough to

scratch rock crystal and steel, but is extremely friable. It has

a specific gravity of 4*87, and on heating combines with the

halogens and oxygen with incandescence.

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