Bonding - Chemistry Encyclopedia

In the everyday world around us, we observe three very different types of materials: gases, liquids, and solids. Closer examination of the physical properties of homogeneous crystalline solids shows that they can be subdivided into four distinct categories according to their physical properties and the different forces holding them together.

Boron - Chemistry Encyclopedia

Boron occurs in nature as part of oxygenated compounds, or borates, that have been known since ancient times for their use in glass and metal production. In 1808 Joseph-Louis Gay-Lussac and Louis Jacques Thenard of France and Humphry Davy of England discovered the element boron almost concurrently.

Bromine - Chemistry Encyclopedia

Bromine is a member of a family of elements known as halogens that are found in group 7A of the Periodic Table. Bromine was discovered in 1826 in Montpellier, France, by French chemist Antoine J.

Cadmium - Chemistry Encyclopedia

Cadmium is a silver-white, malleable metal that exists as crystals having the hexagonal close-packed arrangement, and is usually found combined with other elements in mineral compounds (e.g., cadmium oxide, cadmium chloride, cadmium sulfate, and cadmium sulfide). Cadmium dust can ignite spontaneously in air and is both flammable and explosive when exposed to heat, flame, or oxidizing agents.

Caffeine - Chemistry Encyclopedia

Caffeine belongs to the family of heterocyclic compounds known as purines. It has the systematic name 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione; it is also known as 1,3,7-trimethylxanthine, and 1,3,7-trimethyl-2,6-dioxopurine.

Calcium - Chemistry Encyclopedia

Calcium is the fifth most abundant element in Earth's crust, with calcium oxide, CaO (lime), being among the most common of all terrestrial compounds. Calcium is very important from a biological standpoint, being critical to bones, teeth, and shells of various animals, most often appearing in the form of insoluble calcium phosphate, Ca3(PO4)2.

Californium - Chemistry Encyclopedia

Carbohydrates - Chemistry Encyclopedia

Carbohydrates are the most abundant natural organic compounds on Earth. The term "carbohydrate" derives from their general formula of Cn(H2O)n, first determined in the nineteenth century, and indicates that these compounds are hydrates of carbon.

Carbon - Chemistry Encyclopedia

Carbon is the sixth most abundant element in the universe and possibly the most widespread element on earth. Named from the Latin word carbo, meaning charcoal, it has been known since ancient times, although not recognized as an element until more modern times.

Carcinogen - Chemistry Encyclopedia

A carcinogen is a substance that can cause cancer in humans or animals. Carcinogens bring about molecular and biochemical disturbances in cells, resulting in dedifferentiation (the loss of cells' morphological and functional specializations, such that they behave like immature cells capable of resuming cell division) and uncontrolled growth (neoplasia).

Careers in Chemistry - Chemistry Encyclopedia

An undergraduate program in chemistry prepares the ground for many possible career paths, including industry, graduate work, and professional programs.

Catalysis and Catalysts - Chemistry Encyclopedia

Catalysis is an acceleration or retardation of the rate of a chemical reaction, brought about by the addition of a substance (the catalyst) to the reaction medium. The catalyst, usually present in small amounts, is not consumed in the reaction.

Henry Cavendish - Chemistry Encyclopedia

Henry Cavendish, born in Nice, France to an aristocratic English family, was an avid and excellent experimenter. At the age of forty, he inherited an immense fortune that afforded him the luxury of pursuing his scientific interests (he was described by some as the "richest of all the learned and the most learned of all the rich").

Cellulose - Chemistry Encyclopedia

Cellulose is the most abundant organic molecule in nature. It is a polysaccharide assembled from glucose monomer units, and it (together with other materials such as hemicellulose and lignin) is the main constituent of plant cell walls.

Ceramics - Chemistry Encyclopedia

Ceramics can be defined as heat-resistant, nonmetallic, inorganic solids that are (generally) made up of compounds formed from metallic and nonmetallic elements. Although different types of ceramics can have very different properties, in general ceramics are corrosion-resistant and hard, but brittle.

Cerium - Chemistry Encyclopedia

In 1751 the Swedish chemist Axel F. Cronstedt found, near Bastnäs, Sweden, a mineral that was eventually named cerita (its name related to the planetoid Ceres).

Ludwig Boltzmann - Chemistry Encyclopedia

Ludwig Edward Boltzmann is one of the foremost theoretical physicists of the latter nineteenth century. A vigorous advocate for the existence of atoms, he made monumental contributions to the kinetic theory of gases and established the statistical nature of the second law of thermodynamics.

Robert Boyle - Chemistry Encyclopedia

Robert Boyle was born in 1627, the youngest son of a large upper-class English family with significant landholdings in Ireland and ties to both sides of the English Civil War (1642–1651).

William Henry Bragg - Chemistry Encyclopedia

Sir William Henry Bragg was born on July 2, 1862, near Wigton in the northwest of England, the son of an officer in the merchant navy. He attended King William's College on the Isle of Man, before studying for the mathematical degree at Trinity College, Cambridge, in 1884.

William Lawrence Bragg - Chemistry Encyclopedia

Sir William Lawrence Bragg was born on March 31, 1890, in Adelaide, South Australia, where his father, William Henry Bragg, was professor of mathematics and physics. Lawrence attended St.

Johannes Nicolaus Brønsted - Chemistry Encyclopedia

Johannes Nicolaus Brønsted was a physical chemist whose work resulted in a new theory of acids and bases. He was born in the town of Varde in Jutland (Denmark), where his father was an engineer for the Danish Heath Society.

Robert Bunsen - Chemistry Encyclopedia

Robert Wilhelm Bunsen, born in Göttingen, is often identified with the laboratory burner that bears his name. But to think of him only in relation to the Bunsen burner is to do him a disservice.

Mary Caldwell - Chemistry Encyclopedia

During the early part of the twentieth century, women were rarely able to find a career related to chemistry. However, there were three particular fields that were havens for women: crystallography (to which physicist Dorothy Hodgkin contributed); radioactivity (a field that physicist Lise Meitner and chemist Marie Curie excelled in); and biochemistry, where Mary Caldwell was able to pursue a lifelong career.

Melvin Calvin - Chemistry Encyclopedia

Melvin Calvin was born to immigrant parents on April 8, 1911, in St. Paul, Minnesota.

Stanislao Cannizzaro - Chemistry Encyclopedia

Born in Palermo, Sicily, in 1826, Stanislao Cannizzaro began medical studies at the University of Palermo before moving to Pisa to study chemistry. However, when the Sicilian revolt broke out in 1848, Cannizzaro took part in the capture of Messina.

Sadi Carnot - Chemistry Encyclopedia

Nicolas-LĂ©onard-Sadi Carnot was born in 1796 in Paris. He is known as the father of thermodynamics.

Wallace Carothers - Chemistry Encyclopedia

Wallace Hume Carothers, one of the founders of the modern synthetic materials industry, was born in Burlington, Iowa, on April 27, 1896.

George Washington Carver - Chemistry Encyclopedia

George Washington Carver was born on a Missouri farm near Diamond Grove sometime toward the end of the U.S. Civil War.