SOC  . 1907, ii . 557.)

Titanium fluoride, TiF4, is a fuming colourless liquid boiling at 284°, obtained by distilling a mixture of titanium oxide, fluorspar and sulphuric acid; by heating barium titanofluoride, BaTiF5 (Emrich, Monats., 1904, 25, p . 907) ; and by the action of dry hydrofluoric acid on the chloride (Ruff and Plato, Ber., 1904, 37, p . 673) . By dissolving the dioxide in hydrofluoric acid a syrupy solution is obtained which probably contains titanofluoric acid, IhTiF6 . The salts of this acid are well known; they are isomorphous with the silico-, stanno- and zircono-fluorides . They are obtained by neutralizing the solution of the acid, or by fusing the oxide with potassium carbonate and treating the melt with hydrofluoric acid . Potassium titanofluoride . K2TiFs-H2O, forms white, shining, monoclinic scales . When ignited in a current of hydrogen it yields titanium trifluoride, TiF3, as a violet powder . Titanium chloride, TiC14, is obtained as a colourless fuming liquid of 1.7604 sp. gr. at o° C.. boiling at 116.4° under 753.3 mm. pressure (T .

E .

Thorpe), by heating to dull redness an intimate dry mixture Of the oxide and ignited lamp-black in dry chlorine . In the method of A . Stabler and H . Wirthwein, the titanium mineral is fused withcarbon in the electric furnace, the carbides treated with chlorine, and the titanium chloride condensed . The distillate is freed from vanadium by digestion with sodium amalgam . Other methods are due to E . Vigouroux and G . Arrivaut (Abst . Journ . Chem . Soc., 1907, ii .

97, 270) and

Ellis (ibid., p . 270) . By passing chloroform vapour over the heated dioxide the tetra- di- and tri-chlorides are formed, together with the free metal and a gaseous hydride, TiH4 (Renz, Ber., 1906, 39, p . 249) . When dropped very cautiously into cold water it dissolves into a clear solution . According to the amount of water used, TiC13OH, TiCl2(OH)2, TiCI(OH)3 or titanic acid is formed . The solution when boiled deposits most of its oxide in the meta-hydrate form . It forms addition compounds similar to those formed by stannic chloride, and combines with ammonia to form TiCI4.8NH3 and TiC14.6NH3, both of which with liquid ammonia give titanamide, Ti(NH2)4 . Titanium dichloride, TiCl2, obtained by passing hydrogen over the trichloride at a dull red heat, is a very hygroscopic brown powder which inflames when exposed to air, and energetically decomposes water . Titanium trichloride, TiCla, forms involatile, dark violet scales, and is obtained by passing the vapour of the tetrachloride mixed with hydrogen through a red-hot tube, or by heating the tetrachloride with molecular silver to 200° . It is a powerful reducing agent . Titanium tetrabromide, TiBr4, is an amber-coloured crystalline mass .

The tetraiodide, TiI4, is a reddish brown mass having a metallic lustre . The di-iodide, TiI2, is obtained as black lamella by passing the vapour of the tetraiodide over heated

mercury in an atmosphere of hydrogen (E . Defacqz and H . Copaux, Compt. rend., 1908, 147, p . 65) . Sulphides are known corresponding to the best-known oxides . Titanium sesquisulphate, Ti2(SO4)i.8H2O, obtained by concentrating the violet solution formed when the metal is dissolved in sulphuric acid, is interesting since it forms a caesium alum, CsTi(SO4)2.12H2O . It gives the normal sulphate as a yellow, deliquescent, amorphous mass when treated with nitric acid . Acid solutions of titanates are not precipitated by suiphuretted hydrogen ; but ammonium sulphide acts on them as if it were ammonia, the suiphuretted hydrogen being liberated . Titanium oxide when fused with microcosmic salt in the oxidizing flame yields a bead which is yellowish in the heat but colourless after cooling . In the reducing flame the bead becomes violet, more readily on the addition of tin; in the presence of iron it becomes blood-red . Titanic oxides when fused on charcoal, even with potassium cyanide, yield no metal .

Rose determined the atomic weight to be 47.72 (H = i ) . A redetermination in 1885 by T . E . Thorpe gave the value 47.7 (see Journ . Chem . Soc., 1885, p . 108) .