As obtained by Moissan in the fused condition by means of an electric furnace, although not quite free from carbon, metallic titanium is not unlike silicon, but whiter, lustrous, very hard, but brittle, of specific gravity 4.87. It burns when heated in the air, and is attacked by the common mineral acids, a light strong grey lustrous corrosion-resistant metallic element used in strong lightweight alloys (as for airplane parts); the main sources are rutile and ilmenite, A chemical element, atomic number 22; it is a strong, corrosion-resistant transition metal, used to make light alloys for aircraft etc.

a tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors, Chemical symbol, Si; atomic weight, 28. 19. A non-metallic element which is obtained in three allotropic forms?namely, amorphous, as a dull-brown powder soluble in alkali, which burns when ignited; graphitic, in crystalline leaves having a strong metallic luster and lead-gray color, insoluble in alkali and non-combustible; and crystalline, in octahedral needles having a red luster, and hardness a little less than that of the diamond, Elementary silicon can now he prepared in large qnantity by electrolysis, and in a fused condition. Like its oxid, in cooling from a state of fusion it passes through a plastic stage in which it can be molded into special forms or drawn into threads