Columbia Encyclopedia

Search results

276 results found

hydroxyl group

(Encyclopedia)hydroxyl group hīdrŏkˈsĭl [key], in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by ...

Wurtz, Charles Adolphe

(Encyclopedia)Wurtz, Charles Adolphe shärl ädôlfˈ vürts [key], 1817–84, French chemist. He was professor at the Sorbonne (1852–75), at the Faculty of Medicine, Paris (1853–75), and at the Faculty of Scie...

nitrate

(Encyclopedia)nitrate, chemical compound containing the nitrate (NO3) radical. Nitrates are salts or esters of nitric acid, HNO3, formed by replacing the hydrogen with a metal (e.g., sodium or potassium) or a radic...

silicate

(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...

electronegativity

(Encyclopedia)electronegativity ĭlĕkˌtrōnĕgətĭvˈətē [key], in chemistry, tendency for an atom to attract a pair of electrons that it shares with another atom (see chemical bond). For example, the molecule...

depilatory

(Encyclopedia)depilatory dĭpĭlˈətôrˌē [key], substance used to remove hair. In preparing hides for tanning, lime is the chief depilatory. For the removal of superfluous hair from the human body, metal sulfid...

Davy, Sir Humphry

(Encyclopedia)Davy, Sir Humphry, 1778–1829, English chemist and physicist. The son of a woodcarver, he received his early education at Truro and was apprenticed (1795) to a surgeon-apothecary at Penzance. While d...

airglow

(Encyclopedia)airglow, faint diffuse illumination of the sky originating in the upper atmosphere. Although it occurs at all times of day throughout the upper atmosphere, it is most typically visible to an observer ...

Bordeaux mixture

(Encyclopedia)Bordeaux mixture bôrdōˈ [key], fungicide consisting of cupric sulfate and lime in water. Its fungicidal activity is associated with the slow formation of copper compounds, the ultimate toxicant bei...

Carrel, Alexis

(Encyclopedia)Carrel, Alexis kärĕlˈ, kə– [key], 1873–1944, American surgeon and experimental biologist, b. near Lyons, France, M.D. Univ. of Lyons, 1900. Coming to the United States in 1905, he joined the s...