Dictionary of Chemistry [6th Ed.]

maintain moisture levels. Humec- tants are generally *hygroscopic. For example, glycerol is employed as a humectant in confectio ...

hydrideA chemical compound of hydrogen and another element or el- ements. Non-metallic hydrides (e.g. ammonia, methane, water) a ...

industrial processes, such as the reduction of oxide ores, the reÜning of petroleum, the production of hydrocarbons from coal, a ...

Hydrogen bonds are not purely elec- trostatic and can be shown to have some covalent character. hydrogen bromide A colourless ga ...

or hydriodic acid). It is also a reduc- ing agent. hydrogen ion See acids. hydrogen molecule ion The sim- plest type of molecule ...

(see kipp’s apparatus). Solutions in water (known as hydrosulphuric acid) contain the anions HS–and minute traces of S2–and are ...

4-hydroxybutanoic acid lactone (γ-butyrolactone) A colourless liquid *lactone, C 4 H 6 O 2 ; b.p. 206°C. It is used as a solvent ...

I ice See water. ice pointThe temperature at which there is equilibrium between ice and water at standard atmos- pheric pressure ...

implosionAn inward collapse of a vessel, especially as a result of evacu- ation. IMSSee ion-mobility spectrometry. incandescence ...

2 pH units. In titration, the point at which the reaction is complete is the equivalence point (i.e. the point at which equivale ...

inductive effect The effect of a group or atom of a compound in pulling electrons towards itself or in pushing them away. Induct ...

frequencies. The frequencies of most interest range from 2.5 to 16 μm; however, in IR spectroscopy it is common to use the recip ...

concentration in the blood. Insulin was theÜrst protein whose amino- acid sequence was fully determined (in 1955). Underproducti ...

electromagnetic coupling to one of the bound electrons of that atom rather than being released as a pho- ton. The coupling is us ...

inversionA chemical reaction in- volving a change from one optically active conÜguration to the opposite conÜguration. The Walde ...

has either lost one or more electrons, making it positively charged (a cation), or gained one or more elec- trons, making it neg ...

ionization of a solvent the ionic prod- uct is also called the autoprotolysis constant. See also solubility product; ph scale. i ...

strongly bound electron is the Ürst ionization potential. Second, third, and higher ionization potentials can also be measured, ...

referred to as gas-phase electro- phoresis. ionophore A relatively small hy- drophobic molecule that facilitates the transport o ...

iron(II) chloride A green-yellow deliquescent compound, FeCl 2 ; hexagonal; r.d. 3.16; m.p. 670°C. It also exists in hydrated fo ...