Intimate/contact/tight

Organic ion radicals exist together with counterions and often form ion pairs. Since the pioneering works of Grunwald (1954), Winstein with co-authors (1954) and Fuoss and Sadek (1954), the terms contact, tight, or intimate ion pair and solvent-separated or loose ion pair have become well known in the chemical world. More recently, Marcus (1985) and Boche (1992) introduced other colloquial expressions, the solvent-shared ion pair and the penetrated ion pair. 

Table V shows that the vast majority of the titratable groups of the smaller protein molecules have pK nt values which are quite close to the values predicted from the pK s of model compounds. This feature of protein titration curves has been well known for a long time, and is accepted as normal. It is however really an astonishing result, for it implies that most of the titratable groups of the smaller protein molecules are in as intimate contact with the solvent as similar groups on smaller molecules, and that they are able to accept or release hydrogen ions in this location without requiring any modification of the protein conformation in the vicinity of the titratable group. Since most of the proteins examined have been globular proteins, tightly folded so as to exclude solvent from most of the interior portions, the titratable groups must be nearly always at the surface.

Agitation is generally necessary to bring liquid and solid phases into intimate contact and facilitate equilibration. Agitation with a stirrer in an open vessel is not normally recommended, on account of the potential loss of solvent by evaporation, but sealed-agitated vessels are commonly used. Agitation in tightly stoppered vessels, that are rocked, rotated or shaken whilst immersed in a thermostat bath, is also quite a popular method, particularly when many samples have to be tested at the same time. 

Sherardizing n. Method of coating steel or cast iron articles in intimate contact with zinc. The articles are heated with zinc dust for several hours. The zinc forms an alloy, at the interface of the ferrous surface, thus producing a thin, tightly adherent coating. 

To explain the adhesion of isocyanate-based adhesives to impervious, apparently unreactive surfaces such as glass and metals, it is considered that isocyanate groups react with the molecular film of tightly absorbed water always present on such surfaces, the reaction of the isocyanate groups with the oxyhydrate layer on metal surfaces and isocyanate polymerization on (alkaline) glass. All of these processes provide intimate contact if not actual chemical bonds between adhesive and adherend. 

Pressure-sensitive adhesives are permanently tacky and flow under pressure to provide intimate contact with the adherend surface. Pressure-sensitive tapes are made by placing these adhesives on a backing material such as rubber, vinyl, canvas, or cotton cloth. After pressure is applied, the adhesive tightly grips the part being mounted as well as the surface to which it is affixed. The ease of application and the many different properties that can be obtained from elastomeric adhesives account for their wide use. 

Contact Ion Pair—synonymous with tight or intimate ion pair ... 

An ion pair, the constituent ions of which are in direct contact (and not separated by an intervening solvent or other neutral molecule), is designated as a tight ion pair (or intimate or contact ion pair ). A tight ion pair of X+ and Y is symbolically represented as X+Y. ... 

In real ionic polymerization systems, however, more than one kind of ion occurs, especially in the case of anionic polymerizations. A distinction is made between free ions, solvated ion pairs (solvent separated or loose ion pairs), contact ion pairs (intimate ion pairs or tight ion pairs), polarized molecules, and ionic associates of three or more ions. A rapid dynamic equilibrium often occurs between these ionic forms ... 

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