how many elements and which elements did you find in carbide
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Carbide, any of a class of chemical compounds in which carbon is combined with a metallic or semimetallic element. Calcium carbide is important chiefly as a source of acetylene and other chemicals, whereas the carbides of silicon, tungsten, and several other elements are valued for their physical hardness, strength, and resistance to chemical attack even at very high temperatures. Iron carbide (cementite) is an important constituent of steel and cast iron.
Carbides are prepared from carbon and an element of similar or lower electronegativity, usually either a metal or a metal oxide, at temperatures of 1,000–2,800 °C (1,800–5,100 °F). Almost any carbide can be prepared by one of several general methods. The first method involves direct combination of the elements at high temperatures (2,000 °C [3,600 °F] or higher). The second method is the reaction of a compound of a metal, usually an oxide, with carbon at high temperature. Two additional methods involve reaction of a metal or metal salt with a hydrocarbon, usually acetylene, C2H2. In one of the methods, the heated metal reacts with a gaseous hydrocarbon; in the other, a metal is dissolved in liquid ammonia, NH3, and the hydrocarbon is bubbled through the solution. Carbides that are prepared with acetylene are called acetylides and contain the C22− anion. For example, the alkali metal acetylides are best prepared by dissolving the alkali metal in liquid ammonia and passing acetylene through the solution. These compounds, which have the general formula M2C2 (where M is the metal), are colourless, crystalline solids. They react violently with water and, when heated in air, are oxidized to the carbonate. The alkaline-earth carbides also are acetylides. They have the general formula MC2 and are prepared by heating the alkaline-earth metal with acetylene above 500 °C (900 °F).
Classification Of Carbides
Classification of carbides based on structural type is rather difficult, but three broad classifications arise from general trends in their properties. The most electropositive metals form ionic or saltlike carbides, the transition metals in the middle of the periodic table tend to form what are called interstitial carbides, and the nonmetals of electronegativity similar to that of carbon form covalent or molecular carbides.
Ionic carbides
Ionic carbides have discrete carbon anions of the forms C4−, sometimes called methanides since they can be viewed as being derived from methane, (CH4); C22−, called acetylides and derived from acetylene (C2H2); and C34−, derived from allene (C3H4). The best-characterized methanides are probably beryllium carbide (Be2C) and aluminum carbide (Al4C3). Beryllium oxide (BeO) and carbon react at 2,000 °C (3,600 °F) to produce the brick-red beryllium carbide, whereas pale yellow aluminum carbide is prepared from aluminum and carbon in a furnace. Aluminum carbide reacts as a typical methanide with water to produce methane.
Al4C3 + 12H2O → 4Al(OH)3