radical


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radical,

in chemistry, group of atoms that are joined together in some particular spatial structure and that take part in most chemical reactions as a single unit. Important inorganic radicals include ammonium, NH4; carbonate, CO3 ; chlorate, ClO3, and perchlorate, ClO4 ; cyanide, CN; hydroxide, OH; nitrate, NO3; phosphate, PO4; silicate, SiO3 (meta) or SiO4 (ortho); and sulfate, SO4. The use of these radicals simplifies the naming and description of inorganic compounds, since such usage does not consider the electronic charge on the group. (When ionsion,
atom or group of atoms having a net electric charge. Positive and Negative Electric Charges

A neutral atom or group of atoms becomes an ion by gaining or losing one or more electrons or protons.
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 are dealt with, electronic charge must be considered.) In organic chemistry, the term radical is sometimes used synonymously with group; e.g., the group CH3 is sometimes called the methyl radical instead of the methyl group. This use is limited chiefly to alkyl groupsalkyl group
, in chemistry, group of carbon and hydrogen atoms derived from an alkane molecule by removing one hydrogen atom (see radical). The name of the alkyl group is derived from the name of its alkane by replacing the -ane suffix with -yl, e.g.
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 and aryl groupsaryl group
, in chemistry, group of atoms derived from benzene or from a benzene derivative by removing one hydrogen that is bonded to the benzene ring (see radical). The simplest aryl group is phenyl, C6H5 ; it is derived from benzene.
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; it is usually not applied to functional groupsfunctional group,
in organic chemistry, group of atoms within a molecule that is responsible for certain properties of the molecule and reactions in which it takes part. Organic compounds are frequently classified according to the functional group or groups they contain.
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, such as carbonyl. Because the term radical easily could be taken to mean a free radicalfree radical,
in chemistry, a molecule or atom that contains an unpaired electron but is neither positively nor negatively charged. Free radicals are usually highly reactive and unstable. They are produced by homolytic cleavage of a covalent bond (see chemical bond); i.e.
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, the term group is preferred by some.

radical,

in mathematics, symbol (√) placed over a number or expression, called the radicand, to indicate a rootroot,
in mathematics, number or quantity r for which an equation f(r)=0 holds true, where f is some function. If f is a polynomial, r is called a root of f; for example, r=3 and r
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 of the radicand. When used without a sign or index number, as in √4, it designates the positive square root of the radicand, i.e., 2. If both square roots are meant, the radical sign is preceded by ±, as in ±√4. To indicate higher roots of the radicand, e.g., cube or fourth roots, an index number is used, as in ∛27. The radical sign is generally taken to indicate the principal root of the radicand, i.e., ∛27 = 3, although any radicand will have n different nth roots. The term radical is sometimes used loosely to refer to the entire expression consisting of radical sign and radicand.

Radical

(religion, spiritualism, and occult)

Radical is an adjective form of the noun radix, as in the “radical” position of the planets, meaning their original position in a horoscope chart.

Radical

 

(1) In capitalist countries, a member of a political party that demands in its program bourgeois-democratic reforms within the framework of the existing system.

(2) One who advocates a radical solution to problems.

radical

[′rad·ə·kəl]
(botany)
Of, pertaining to, or proceeding from the root.
Arising from the base of a stem or from an underground stem.
(mathematics)
In a ring, the intersection of all maximal ideals. Also known as Jacobson radical.
An indicated root of a quantity. Symbolized √.
(organic chemistry)

radical

1. favouring or tending to produce extreme or fundamental changes in political, economic, or social conditions, institutions, habits of mind, etc
2. Med (of treatment) aimed at removing the source of a disease
3. of, relating to, or arising from the root or the base of the stem of a plant
4. Maths of, relating to, or containing roots of numbers or quantities
5. a person who favours extreme or fundamental change in existing institutions or in political, social, or economic conditions
6. Maths a root of a number or quantity, such as 3&#221A5, &#221Ax
7. Chem
a. short for free radical
b. another name for group
References in periodicals archive ?
It seems that at the end of the 19th century, a period regarded as both a low-point in the history of German liberalism and as a period in which North German liberalism was attempting to decide on the path to take in the future, (64) in Greater Swabia as well as other regions a special German model of a radical democratic movement came into being.
As to the for radicals constraint, it is precisely the overall accessibility of both the format and the actual content of this book that is most suggestive of its capacity to aid in the general promotion of radical ideas.
Free radical damage could also be designated as oxidation--a process of adding oxygen to a substance comparable to the way rust is added to metal.
With the exception of Radical-ruled Tennessee, the Radical Republicans did not yet possess sufficient control in any of the other former Confederate states to ratify the 14th Amendment.
Now that it's a winner, Stafford and Little will take Radical Simplicity to Japan to tour around motorcycle shows.
16) For more on Briggs and Garvey, see Theman Thomas, "Cyril Briggs and the African Blood Brotherhood: Another Radical View of Race and Class During the 1920s," Diss.
When the researchers tested the effects of pollen extracts on cells taken from the lining of the lung, they found that adding NADPH oxidase increased the intracellular levels of free radicals.
In the 1997 issue of Library Trends, Children and the Digital Library, Dresang (1997) introduced the theory of Radical Change for the first time in a scholarly publication.
ORB is a new class of rechargeable battery being uniquely developed by NEC, which uses the electrochemical reaction of organic radical compounds.
Other excellent books--such as Todd Gitlin's The Sixties, Hugh Pearson's The Shadow of the Panther, and Thomas Powers's Diana: The Making of a Terrorist--tell the story of that era without sugarcoating the deeds of the radical youth who wanted to impose a social revolution.
Radical oxygen species and radical nitrogen species initiate the apoptotic cascade.