He was the first to discover uranium, zirconium and titanium, and to characterize them as distinct elements, though he did not obtain any of them in the pure metallic state; and he elucidated the composition of numerous substances till then imperfectly known, including compounds of the then newly recognized elements: tellurium, strontium, cerium and chromium.
Carbon was joined with silicon, zirconium and titanium, while boron, being trivalent, was relegated to another group. A general classification of elements, however, was not realized by Frankland, nor even by Odling, who had also investigated the question from the valency standpoint.
In the same year as Klaproth detected uranium, he also isolated zirconia or zirconium oxide from the mineral variously known as zircon, hyacinth, jacynth and jargoon; but he failed to obtain the metal, this being first accomplished some years later by Berzelius, who decomposed the double potassium zirconium fluoride with potassium.
In the following year, 1795, Klaproth announced the discovery of a third new element, titanium; its isolation' (in a very impure form), as in the case of zirconium, was reserved for Berzelius.
In 1824 he obtained zirconium from potassium zirconium fluoride; the preparation of (impure) titanium quickly followed, and in 1828 he obtained thorium.
Rosenbuschite, hiortdahlite, and some other rare members containing zirconium and fluorine, occur as accessory constituents in the nephelinesyenite of southern Norway.
In 1858 he pointed out the isomorphism of the fluostannates and the fluosilicates, thus settling the then vexed question of the composition of silicic acid; and subsequently he studied the fluosalts of zirconium, boron, tungsten, &c., and prepared silicotungstic acid, one of the first examples of the complex inorganic acids.
In its chemical relations, titanium is generally tetravalent, and occurs in the same sub-group of the periodic classification as zirconium, cerium and thorium.
ZIRCONIUM [[[symbol]] Zr, atomic weight 90 6 (0= 16)], a metallic chemical element.
Troost produced crystallized zirconium by fusing the double fluoride with aluminium in a graphite crucible at the temperature of melting iron, and extracting the aluminium from the melt with hydrochloric acid.
In its chemical affinities zirconium resembles titanium, cerium and thorium; it occurs in company with these elements, and is tetravalent in its more important salts.
Zirconium oxide or zirconia, Zr02, has become important since its application to the manufacture of mantles for incandescent gas-lighting.
Zirconium hydroxide, Zr(OH) 4, as thus obtained, is quite appreciably soluble in water and easily in mineral acids, with formation of zirconium salts, e.g.
Zirconium hydride, ZrH2, is supposed to be formed when zirconia is heated with magnesium in an atmosphere of hydrogen.
Zirconium fluoride, ZrF4, is obtained as glittering monoclinic tables (with 3H 2 0) by heating zirconia with acid ammonium fluoride.
Zirconium chloride, ZrC1 4, is prepared as a white sublimate by igniting a mixture of zirconia and charcoal in a current of chlorine.
Zirconium bromide, ZrBr 4, is formed similarly to the chloride.
Zirconium iodide, Zr14, was obtained as a yellow, microcrystalline solid by acting with hydriodic acid on heated zirconium (Wedekind, Ber., 1904, 37, p. 1135).
It fumes in air; with water it gives ZrOI 2.8H 2 0; and with alcohol ethyl iodide and zirconium hydroxide are formed.
Zirconium combines with sulphur to form a sulphide, and with carbon to form several carbides.
Zirconium also forms double sulphates of the type Zr203(S04M)2 nH20, where M =K, Rb, Cs, and n=8 for K, 15 for Rb, 11 for Cs (Rosenheim and Frank, Ber., 1905, 38, p. 812).