montmorillonite


montmorillonite
montmorillonitic /mont'meuh ril'euh nit"ik/, adj.
/mont'meuh ril"euh nuyt'/, n.
any of a group of clay minerals characterized by the ability to expand when they absorb large quantities of water. Also called smectite.
[1850-55; named after Montmorillon, France, where it was found; see -ITE1]

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      any of a group of clay minerals and their chemical varieties that swell in water and possess high cation-exchange capacities. The theoretical formula for montmorillonite (i.e., without structural substitutions) is (OH)4 Si8 Al4 O20·nH2 O.

      The montmorillonite minerals are composed of hydrous aluminum silicates in the form of extremely small particles. They take up water between their layers, causing swelling, and change the interlayer spacing according to the mineral variety. In addition to being involved in inorganic exchange reactions, they react with and absorb some organic liquids, such as amines, glycols, glycerols, and other polyhydric alcohols. For detailed physical properties, see clay mineral (table). These minerals are used as bleaching earths for clarifying water, juices, and liquors and for removing colour from mineral and vegetable oils; they are also used as catalyst supports and absorbents in petroleum refining. Montmorillonites are the principal constituents of bentonite and fuller's earth. Montmorillonite-saponite originally denoted fuller's earth, and the term later was applied to the montmorillonite mineral and certain clay deposits that are apparently bentonite and to a greenish variety of halloysite. Montmorillonites are common in clays, shales, soils, Mesozoic and Cenozoic sediments, and nonmicaceous recent marine sediments. They usually occur in areas of poor drainage.

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Universalium. 2010.

Look at other dictionaries:

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  • montmorillonite — noun Etymology: French, from Montmorillon, commune in western France Date: 1854 a soft clayey water absorbent mineral that is a hydrous aluminum silicate • montmorillonitic adjective …   New Collegiate Dictionary

  • montmorillonite — noun any of a group of soft, clay like silicate minerals having many industrial and technical uses …   Wiktionary

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  • montmorillonite — mont·mo·ril·lo·nì·te s.f. TS mineral. minerale di colore verde grigiastro costituito da silicato idrato di alluminio, magnesio e sodio, in grado di assorbire grandi quantità d acqua e utilizzato in varie applicazioni tecniche {{line}} {{/line}}… …   Dizionario italiano

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