Columbia Encyclopedia

Search results

500 results found

transition elements

(Encyclopedia)transition elements or transition metals, in chemistry, group of elements characterized by the filling of an inner d electron orbital as atomic number increases. This includes the elements from titani...

Dauphiné

(Encyclopedia)Dauphiné dōfēnāˈ [key], region and former province, SE France, bordering on Italy. It is now divided into three departments, Haute-Alpes, Isère, and Drôme. In the east the Alps culminate in the...

tin

(Encyclopedia)tin, metallic chemical element; symbol Sn [Lat. stannum]; at. no. 50; at. wt. 118.710; m.p. 231.9681℃; b.p. 2,270℃; sp. gr. 5.75 (gray), 7.3 (white); valence +2 or +4. Tin exhibits allotropy; abov...

periodic table

(Encyclopedia)CE5 periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arrange...

Hofmann, August Wilhelm von

(Encyclopedia)Hofmann, August Wilhelm von ouˈgo͝ost vĭlˈhĕlm fən hôfˈmän [key], 1818–92, German organic chemist. He was professor at the Univ. of Berlin from 1865 and was a founder (1868) of the German C...

Erlenmeyer, Richard A. C. E.

(Encyclopedia)Erlenmeyer, Richard A. C. E. ĕrˈlənmīˌər [key], 1825–1909, German chemist. He studied at Giessen under Justus von Liebig and at Heidelberg under Friedrich Kekulé, both German chemists. Erlenm...

Frankland, Sir Edward

(Encyclopedia)Frankland, Sir Edward, 1825–99, English chemist. He studied under Bunsen and Liebig and taught at several English institutions. In working on the synthesis and isolation of compounds he evolved the ...

chemical bond

(Encyclopedia)chemical bond, mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the for...

francium

(Encyclopedia)francium frănˈsēəm [key] [from France], radioactive chemical element; symbol Fr; at. no. 87; mass no. of most stable isotope 223; m.p. about 27℃ (estimated); b.p. 677℃ (estimated); sp. gr. unk...