TITANIUM (Ti). This metal does not occur in the free state in nature, but as a binoxide (titanic acid) it is not uncommon. In the Letter condition, associated with protoxide of iron, it forme titaniferens iron-ore, deposits of which are found in various parts of the world. [Trrsivar, in NAT. liter. Div.] The variety known as ilmenito is met with in larFe quantity in Cana la. At Bay St. Paul, on the St. Lawrence, ilmenito is found in large beds from one to three hundred feet long, and ninety feet thick. It is massive, of ep. gr. and con tains, according to an analysis by Mr. S. Hunt Another kind of titaniferous iron-ore is met with in enormous quan tity in New Zealand, forming, in the state of fine sand, a beach at New Plymouth several miles hi extent. The following analyses of specimens taken from different parts of the deposit, will at once indicate the nature of this deposit A combination of cyanide and nitride of titanium (TiCy,3Ti,N) in the form of reddish-brown metallic-hooking cubes, is nearly always found among the slap and cinders that occur in the bottom of iron furnaces. These crystals are hard enough to scratch agate, and are attacked only by a mixture of nitric and hydrofluoric acid, or by fusion with nitre.
Titanium may be isolated by heating vellum in the vapour of bichlo ride of titanium. The small prime thus obtained are soluble in hydro chloric acid with evolution of nitrogen.
The equivalent of titanium is 25.
Oxygen and titanium appear to form throe compounds :--- Prolorids of titanium (TIO).—When titanic) acid is exposed to a strong heat, a portion of it loses oxygen, and a black mesa in formed, which is probably the protoxide. It has an earthy fracture, is insoluble in acids, and is difficult to reconvert to the titanic acid. It has been already mentioned in the Natural History Division of this that anatase is probably the protoxidc of titanium.
Sesguioxide of titanium TiO,).—When rutile or titanic acid is dissolved in hydrochloric acid, a piece of zinc immersed in the aolution occasions the formation and precipitation of a deep purple coloured powder, which is hydrated seequioxide of titanium, It returns to the state of peroxide very rapidly. It is slightly soluble in
hydrochloric acid, forming a blue solution.
Peroxide of Titanium, Titanic Acid (TiO,).—Rutile is titanic acid nearly pure ; when it is reduced to fine powder and fused in a platinum crucible, with three times its weight of carbonate of potash, titanate of potash is obtained; mixed with some excess of carbonate of potash ; this is to be removed by washing with water, and titanio acid is then precipitated by dilution and heat; after washing with dilute hydro chloric acid it is nearly pure. It is quite white, very infusible, and after it has been heated is soluble only in hydrofluoric acid. Its acid powers are feeble ; it is insoluble in water, and does not act on vege table blues ; it combines, however, with alkalies and metallic oxides, forming salts which are termed titanatcs.
Titanic acid somewhat resembles stannic and ailicie acids. It may be separated from the latter by fusion with bisulphate of potash and sub sequent solution of the mass In water, silica remaining insoluble.
Bichloride of Titanium (TiCl,) is formed when chlorine gas is passed over metallic titanium at a red heat. It is a colourless transparent fluid, boils at 277', and is volatilised, and condenses unchanged. When exposed to the air it deliquesces, and when a few drops of it are mixed with an equal bulk of water, combination takes place with considerable violence and the evolution of intense heat. It absorbs dry ammoniacal gas, and forms ammonia-chloride of titanium (2NU„ TiCl).
Tests for Titanium.—Tinoture of galls or ferrocyanide of potassium produce, when added to a solution of titanic acid, an orange-red pre cipitate.
The other compound° of titanium are but little known. The metal is always estimated in the form of titanic, acid.