instance_of beryllium carbide
A ___MASK82___ ( from Greek  " métallon ", " mine , quarry , ___MASK82___ ") is a material ( an element , compound , or alloy ) that is typically hard , opaque , shiny , and has good electrical and thermal conductivity . Metals are generally malleable  that is , they can be hammered or pressed permanently out of ___MASK75___ without breaking or cracking  as well as fusible ( able to be fused or melted ) and ductile ( able to be drawn out into a thin ___MASK39___ ). About 91 of the 118 elements in the periodic ___MASK29___ are metals , the others are nonmetals or metalloids . Some elements appear in both metallic and non - metallic forms . Silicon carbide ( SiC ), also known as carborundum , is a compound of silicon and carbon with ___MASK24___ formula SiC . It occurs in nature as the extremely rare mineral moissanite . Synthetic silicon carbide powder has been ___MASK98___ - produced since 1893 for use as an abrasive . Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance , such as car brakes , car clutches and ceramic plates in bulletproof vests . Electronic applications of silicon carbide such as light - emitting diodes ( LEDs ) and detectors in early radios were first demonstrated around 1907 . SiC is used in semiconductor ___MASK67___ devices that operate at high temperatures or high voltages , or both . Large ___MASK46___ crystals of silicon carbide can be grown by the Lely method ; they can be cut into gems known as synthetic moissanite . Silicon carbide with high surface area can be produced from SiO contained in plant material . Chemistry is a ___MASK99___ of physical ___MASK79___ that studies the ___MASK22___ , structure , properties and change of matter . Chemistry includes topics such as the properties of individual atoms , how atoms form chemical bonds to create chemical compounds , the interactions of substances through intermolecular forces that give matter its general properties , and the interactions between substances through chemical reactions to form different substances . An interstitial compound , or interstitial ___MASK77___ , is a compound that is formed when an atom with a small enough ___MASK37___ sits in an interstitial  hole  in a ___MASK82___ lattice . Examples of small atoms are hydrogen , boron , carbon and nitrogen . The compounds are important industrially and include some transition - ___MASK82___ carbides and nitrides . A ___MASK41___ anvil ___MASK51___ ( DAC ) is a high - pressure device used in scientific experiments . It enables the compression of a small ( sub - millimeter - sized ) piece of material to extreme pressures , typically up to around 100  200 gigapascals , although it is possible to achieve pressures up to 770 gigapascals ( 7 , 700 , 000 bars / 7 . 7 million atmospheres ). A covalent ___MASK49___ , also called a molecular ___MASK49___ , is a chemical ___MASK49___ that involves the sharing of ___MASK83___ pairs between atoms . These ___MASK83___ pairs are known as shared pairs or bonding pairs , and the stable balance of attractive and repulsive forces between atoms , when they share electrons , is known as covalent bonding . For many molecules , the sharing of electrons allows each atom to attain the equivalent of a full outer shell , corresponding to a stable electronic configuration . Calcium carbide is a ___MASK94___ with the chemical formula of CaC . Its main use industrially is in the production of acetylene and calcium cyanamide . In ___MASK33___ , thermal conductivity ( often denoted " k ", "  ", or "  ") is the ___MASK55___ of a material to conduct heat . It is evaluated primarily in terms of Fourier ' s Law for heat conduction . In chemistry , the ___MASK25___ transition ___MASK82___ ( or transition element ) has three possible meanings : A ___MASK95___ or crystalline solid is a solid ___MASK26___ whose constituents ( such as atoms , molecules , or ions ) are arranged in a highly ordered microscopic ___MASK57___ , forming a ___MASK95___ lattice that extends in all directions . In addition , macroscopic ___MASK46___ crystals are usually identifiable by their geometrical shape , consisting of flat faces with specific , characteristic orientations . The scientific study of crystals and ___MASK95___ formation is known as crystallography . The process of ___MASK95___ formation via mechanisms of ___MASK95___ growth is called crystallization or solidification . In chemistry , a carbide is a compound composed of carbon and a less electronegative element . Carbides can be generally classified by ___MASK24___ bonding type as follows : ( i ) salt - like , ( ii ) covalent compounds , ( iii ) interstitial compounds , and ( iv ) " intermediate " transition ___MASK82___ carbides . Examples include calcium carbide ( CaC ), silicon carbide ( SiC ), tungsten carbide ( WC ) ( often called simply " carbide " when referring to machine tooling ), and cementite ( FeC ), each used in key industrial applications . The naming of ionic carbides is not systematic . Tungsten carbide ( ___MASK24___ formula : WC ) is a ___MASK94___ ( specifically , a carbide ) containing equal parts of tungsten and carbon atoms . In its most basic form , tungsten carbide is a fine gray powder , but it can be pressed and formed into shapes for use in industrial machinery , cutting tools , abrasives , armor - piercing rounds , other tools and instruments , and jewelry . ___MASK26___ is a broad term for a ___MASK24___ substance or mixture of substances that constitute a thing . Beryllium carbide , or Be2C , is a ___MASK82___ carbide . Similar to diamond , it is a very hard compound . Cementite , also known as iron carbide , is an ___MASK19___ compound of iron and carbon , more precisely an intermediate transition ___MASK82___ carbide with the formula FeC . By weight , it is 6 . 67 % carbon and 93 . 3 % iron . It has an orthorhombic crystal ___MASK57___ . It is a hard , brittle material , normally classified as a ceramic in its pure form , and is a frequent found and important constituent in ferrous metallurgy . While iron carbide is present in most steels and cast irons , it is produced as a ___MASK5___ in the Iron Carbide process , which belongs to the family of alternative ironmaking technologies ___MASK41___ ( or ) is a metastable allotrope of carbon , where the carbon atoms are arranged in a ___MASK71___ of the face - centered cubic crystal ___MASK57___ called a diamond lattice . ___MASK41___ is less stable than graphite , but the conversion rate from diamond to graphite is negligible at standard conditions . ___MASK41___ is renowned as a material with superlative physical qualities , most of which originate from the strong covalent bonding between its atoms . In particular , diamond has the highest hardness and thermal conductivity of any bulk material . Those properties determine the major industrial ___MASK23___ of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells . Carbon ( from " coal ") is a ___MASK24___ element with ___MASK16___ C and atomic number 6 . It is nonmetallic and tetravalent  making four electrons available to form covalent ___MASK24___ bonds . Three isotopes occur naturally , C and C being stable , while C is a radioactive isotope , decaying with a half - life of about 5 , 730 years . Carbon is one of the few elements known since antiquity . A metalloid is any ___MASK24___ element which has properties in between those of metals and nonmetals , or that has a mixture of them . There is neither a standard definition of a metalloid nor complete ___MASK58___ on the elements appropriately classified as such . Despite the lack of specificity , the term remains in use in the literature of chemistry . Graphite , archaically referred to as plumbago , is a crystalline form of carbon , a semimetal , a native element ___MASK72___ , and one of the allotropes of carbon . Graphite is the most ___MASK92___ form of carbon under standard conditions . Therefore , it is used in thermochemistry as the standard ___MASK34___ for defining the heat of ___MASK60___ of carbon compounds . An ___MASK77___ is a ___MASK56___ of metals or a ___MASK56___ of a ___MASK82___ and another element . Alloys are defined by a metallic bonding character . An ___MASK77___ may be a solid solution of ___MASK82___ elements ( a ___MASK46___ phase ) or a ___MASK56___ of metallic phases ( two or more solutions ). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure . Zintl phases are also sometimes considered alloys depending on bond types ( see also : Van Arkel - Ketelaar triangle for information on classifying bonding in binary compounds ). The periodic ___MASK29___ is a tabular arrangement of the chemical elements , ordered by their atomic number ( number of protons ), electron configurations , and recurring chemical properties . This ordering shows " periodic trends ", such as elements with similar behaviour in the same column . It also shows four rectangular blocks with some approximately similar chemical properties . In general , within one row ( period ) the elements are metals on the left , and non - metals on the right .