![]() The study of metallic elements and their alloys makes up a significant portion of the fields of solid-state chemistry, physics, materials science and engineering. The high thermal conductivity of most metals also makes them useful for stovetop cooking utensils. Home electrical systems, for example, are wired with copper for its good conducting properties and easy machinability. Thus, electrical power grids rely on metal cables to distribute electricity. Iron is most commonly used in the form of an alloy, steel, which contains up to 2.1% carbon, making it much harder than pure iron.īecause metals are good conductors of electricity, they are valuable in electrical appliances and for carrying an electric current over long distances with little energy loss or dissipation. They are also the most abundant metals in the Earth's crust. Iron and aluminium are the two most commonly used structural metals. The strength and reliability of metals has led to their widespread use in construction of buildings and other structures, as well as in most vehicles, many appliances and tools, pipes, road signs and railroad tracks. People have been using metals for a variety of purposes since prehistoric times. Mixtures of two or more elements in which the major component is a metal are known as alloys. The bulk of the elements in the periodic table, those to the left of a diagonal line drawn from boron to polonium, are metals. Metals typically are strong, dense, and good conductors of both electricity and heat. The pinnacle of New York's Chrysler Building, the world's tallest steel-supported brick building, is clad with stainless steel. In materials science, composites of more than one constituent material can be designed to have desired properties. Wood is a natural organic material consisting primarily of cellulose fibers embedded in a matrix of organic lignin. For example, a typical rock is an aggregate of several different minerals and mineraloids, with no specific chemical composition. While many common objects, such as an ice cube or a coin, are chemically identical throughout, many other common materials comprise a number of different substances packed together. Likewise, the specific crystal structure adopted by a crystalline solid depends on the material involved and on how it was formed. Solids that are formed by slow cooling will tend to be crystalline, while solids that are frozen rapidly are more likely to be amorphous. Whether a solid is crystalline or amorphous depends on the material involved, and the conditions in which it was formed. These solids are known as amorphous solids examples include polystyrene and glass. In other materials, there is no long-range order in the position of the atoms. Schematic representation of a random-network glassy form (left) and ordered crystalline lattice (right) of identical chemical composition. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identification and chemical composition. Materials science is primarily concerned with the physical and chemical properties of solids. The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). ![]() Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed. The atoms in a solid are bound to each other, either in a regular geometric lattice ( crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. A solid is characterized by structural rigidity and resistance to a force applied to the surface. The molecules in a solid are closely packed together and contain the least amount of kinetic energy. Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). ![]() Single crystalline form of solid insulin. ![]()
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