Dictionary of Chemistry [6th Ed.]

or group approaches the molecule as the other leaves. The transition state is an intermediate state in which both attacking and ...

unpleasant odour; r.d. 1.114 (liquid at 0 °C); m.p. –111.3°C; b.p. 7°C. It is the acid anhydride of malonic acid, from which it ...

2,4,6-trinitrophenol 536 t b.p. 130°C. Like other aluminium alkyls it may be prepared by reacting a Grignard reagent with alumin ...

usually has a lower energy than a singlet state because of the effect of correlations of spin on the Coulomb interactions betwee ...

CaWO 4. The ore is heated with con- centrated sodium hydroxide solution to form a soluble tungstate. The oxide WO 3 is precipita ...

into type A ligands (e.g. F–) which tend to complex with type A metals and type B ligands (e.g. I–), which tend to complex with ...

U ubiquinoneAny of a group of re- lated quinone-derived compounds that serve as electron carriers in the *electron transport cha ...

tracting this has been increased by the depletion of the ozone layer. Most UV radiation for practical use is produced by various ...

acid–base *indicators that changes colour (e.g. red-yellow-orange-green- blue) over a range of pH. unnil-See transactinide eleme ...

uranium series See radioactive series. urea (carbamide)A white crystalline solid, CO(NH 2 ) 2 ; r.d. 1.3; m.p. 135°C. It is solu ...

V vacancySee crystal defect. vacuumA space in which there is a low pressure of gas, i.e. relatively few atoms or molecules. A pe ...

what he had discovered was an im- pure form of chromium. The el- ement was rediscovered and named by Nils Sefström (1787–1854) i ...

a system, then the energy calculated cannot be lower than the actual energy of the ground state of the system. To use variationa ...

547 vitamin A v between ethyne and a compound with an active hydrogen atom, such as alcohol, amine, or carboxylic acid. Addition ...

vitamin B complex 548 v blindness. The role of vitamin A in other aspects of metabolism is less clear. A Information about IUPA ...

from the gut in the presence of a gly- coprotein called intrinsic factor; lack of this factor or deÜciency of B 12 re- sults in ...

vitamin E 550 v in mature animals. Both conditions are characterized by weak deformed bones. A Information about IUPAC nomencla ...

equivalent of the metal. 2.Any other type of electrolytic cell used for measurement. volumeSymbol V. The space occu- pied by a b ...

W Wacker process A process for the manufacture of ethanal by the air ox- idation of ethene. A mixture of air and ethene is bubbl ...

justiÜcation for Walden’s rule is pro- vided by the proportional relation- ship between Λmand the diffusion coefÜcient, D; as D ...