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The Quaternary is a geologic period. Quaternary (an adjective meaning "fourth in order" or "composed of four items") may also refer to: Quaternary (chemistry) (see also Quaternary compound and Quaternary phase) Quaternary structure of proteins; Quaternary sector of the economy, which encompasses knowledge-based services
Quaternary is a term used in organic chemistry to classify various types of compounds (e. g. amines and ammonium salts). [ 1 ] Red highlighted central atoms in various groups of chemical compounds.
The quaternary sector of the economy is based upon the economic activity that is associated with either the intellectual or knowledge-based economy. [1] This consists of information technology; media; research and development; information-based services such as information-generation and information-sharing; and knowledge-based services such as consultation, entertainment, broadcasting, mass ...
With four elements, quaternary phases are more complex. The number of isomers of a ternary compound provide a distinction between inorganic and organic chemistry: "In inorganic chemistry one or, at most, only a few compounds composed of any two or three elements were known, whereas in organic chemistry the situation was very different." [2]
Quaternary ammonium cation. The R groups may be the same or different alkyl or aryl groups. Also, the R groups may be connected. In organic chemistry, quaternary ammonium cations, also known as quats, are positively-charged polyatomic ions of the structure [NR 4] +, where R is an alkyl group, an aryl group [1] or organyl group.
Harvard tied with Dartmouth and Columbia atop the conference at 5-2 this season, but scored head-to-head wins over both teams. Officially, the Ivy League recognized all three teams as co-champions.
In chemistry, a quaternary compound is a compound consisting of exactly four chemical elements. In another use of the term in organic chemistry, a quaternary compound is or has a cation consisting of a central positively charged atom with four substituents, especially organic (alkyl and aryl) groups, discounting hydrogen atoms. [1]
Russia's deputy U.N. ambassador said on Wednesday any decision by President-elect Donald Trump's incoming administration to cut support for Ukraine would be a "death sentence" for the Ukrainian ...