doubly bonded
21Onium compounds — are cations derived by the protonation of mononuclear parent hydrides of elements of the nitrogen group (Group 15), chalcogens (Group 16), or halogens (Group 17), and similar cations derived by the substitution of hydrogen atoms in the former by… …
22Electric motor — For other kinds of motors, see motor (disambiguation). For a railroad electric engine, see electric locomotive. Various electric motors. A 9 volt PP3 transistor battery is in the center foreground for size comparison. An electric motor converts… …
23coordination compound — Chem. complex (def. 10). Also called coordination complex. * * * ▪ chemistry Introduction any of a class of substances with chemical structures in which a central metal atom is surrounded by nonmetal atoms or groups of atoms, called ligands… …
24Acetylacetone — Acac redirects here. For other uses, see ACAC. Chembox new ImageFile=AcacH.png IUPACName=Pentane 2,4 dione OtherNames=Hacac Formula=C5H8O2 MolarMass=100.13 g/mol CASNo=123 54 6 Density=0.98 g/ml MeltingPt=−23 °C BoilingPt=140 °C Solubility=16… …
25Persistent carbene — A stable carbene: isolated 1,3 dimesitylimidazol 2 ylidene in a Schlenk flask (stir bar also present). A persistent carbene (also known as stable carbene or Arduengo carbene) is a type of carbene demonstrating particular stability. The best known …
26pyroxene — pyroxenic /puy rok sen ik/, adj. /puy rok seen, peuh , puy rok seen /, n. any of a very common group of minerals of many varieties, silicates of magnesium, iron, calcium, and other elements, occurring as important constituents of many kinds of… …
27Acid dissociation constant — Acetic acid, a weak acid, donates a proton (hydrogen ion, high …
28isoprenoid — /uy seuh pree noyd/, adj. Chem. pertaining to, derived from, or similar to isoprene. [1955 60; ISOPRENE + OID] * * * or terpene Class of organic compounds made up of two or more structural units derived from isoprene. Isoprene is a five carbon… …
29ion-exchange reaction — ▪ chemical reaction Introduction any of a class of chemical reactions between two substances (each consisting of positively and negatively charged species called ions (ion)) that involves an exchange of one or more ionic components.… …
30alkaline-earth metal — /al keuh luyn errth , lin /, Chem. any of the group of bivalent metals including barium, radium, strontium, calcium, and, usually, magnesium, the hydroxides of which are alkalis but less soluble than those of the alkali metals. [1900 05] * * * ▪… …
