The possible locations around an atom where electrons having specific energy values (quantum number) may be found. The term shell has been replaced with the term energy levels because the te

One of the 116 presently known substances that cannot be decomposed by chemical reaction into a simpler substance. Elements comprise all matter at and above the atomic level. All elements he

A particle of matter that has a negative electric charge of 4.8 E-10 esu and a mass of 9.1E-28g or 1/1837 the mass of a proton. They can be found as a constituent part of an atom orbiting ar

An element's mass displaced by a unit quantity of electricity passage. The formula used on this site is: electrochemical equivalents=kA/n. 'k' is a constant that equals 0.0373100, 'A' is the

Elements that are present in the gaseous state as molecules composed of two atoms. For example: O2, N2, Cl2 and H2 are diatomic.

The ratio of mass to unit volume expressed in grams/cm3 for solids and liquids and grams/liter in gases (density=mass/volume).

The extremely rapid burning of a material. This is much much faster than normal combustion, but slower than detonation.

A reaction where a single compound breaks down into simpler compounds.

ke Nitration T. Zincke, J. Prakt. Chem. 61, 561 (1900). Replacement of ortho- or para-bromine or iodine atoms (but not fluorine or chlorine atoms) in ph

ke Disulfide Cleavage T. Zincke, Ber. 44, 769 (1911). Formation of sulfenyl halides by three essentially similar methods involving the action of chlorin

Zimmermann Reaction W. Zimmermann, Z. Physiol. Chem. 233, 257 (1935). The reaction that occurs between methylene ketones and aromatic polynitro compound

Wurtz Reaction A. Wurtz, Ann. Chim. Phys. [3] 44, 275 (1855); Ann. 96, 364 (1855). Coupling of two alkyl radicals by treating two moles of alkyl halides

Wolff Rearrangement L. Wolff Ann. 394, 25 (1912). Rearrangement of diazoketones to ketenes thermally, photochemically or catalytically. The rearrangemen

Wohl-Ziegler Reaction A. Wohl, Ber. 52, 51 (1919); K. Ziegler et al., Ann. 551, 30 (1942). Allylic bromination of olefins with N-. Peroxides or ultravio

Wohl Degradation; Zemplén Modification A. Wohl, Ber. 26, 730 (1893); 32, 3666 (1899); G. Zemplén, Ber. 59, 1254, 2402 (1926). Method for t

[2,3]-Wittig Rearrangement J. Cast et al., J. Chem. Soc. 1960, 3521; U. Schöllkopf, K. Fellenberger, Ber. 698, 80 (1966); Y. Makisumi, S. Notzumoto, Tetrahedron Lette

[1,2]-Wittig Rearrangement G. Wittig, L. Löhmann, Ann. 550, 260 (1942); G. Wittig, Experientia 14, 389 (1958). Rearrangement of ethers with alkyl l

Williamson Synthesis A. W. Williamson, J. Chem. Soc. 4, 229 (1852). Synthesis of ethers by alkylation of alkoxides with alkyl halides or alkyl sulfates:

Wichterle Reaction O. Wichterle et al., Coll. Czech. Chem. Commun. 13, 300 (1948). Modification of the Robinson annulation, q.v., in which 1,3-dichloro-

Whiting Reaction P. Nayler, M. C. Whiting, J. Chem. Soc. 1954, 4006. Alkynediols are reduced by lithium aluminum hydride in ether or tertiary amines to