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Meta- (chemistry)
In chemistry, meta is a prefix, used for systematic names in IUPAC nomenclature. It has several meanings. *In organic chemistry, meta indicates the positions of Arene substitution patterns, substituents in aromatic cyclic compounds. The substituents have the 1,3-positions, for example in resorcinol. *Meta may also denote the dehydrated form of an acid, salt or organic derivative in a series. For example: **metabisulfite: *: **metaphosphoric acid: *: **Meta-antimonic acid, the dehydrated form of antimonic acid (), is . See also *Arene substitution patterns References {{reflist Chemistry prefixes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during chemical reaction, reactions with other chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prefix
A prefix is an affix which is placed before the stem of a word. Particularly in the study of languages, a prefix is also called a preformative, because it alters the form of the word to which it is affixed. Prefixes, like other affixes, can be either inflectional, creating a new form of a word with the same basic meaning and same lexical category, or derivational, creating a new word with a new semantic meaning and sometimes also a different lexical category. Prefixes, like all affixes, are usually bound morphemes. English has no inflectional prefixes, using only suffixes for that purpose. Adding a prefix to the beginning of an English word changes it to a different word. For example, when the prefix ''un-'' is added to the word ''happy'', it creates the word ''unhappy''. The word ''prefix'' is itself made up of the stem ''fix'' (meaning "attach", in this case), and the prefix ''pre-'' (meaning "before"), both of which are derived from Latin roots. English language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUPAC Nomenclature
IUPAC nomenclature is a set of recommendations for naming chemical compounds and for describing chemistry and biochemistry in general. The International Union of Pure and Applied Chemistry (IUPAC) is the international authority on chemical nomenclature and terminology. History of the Standardisation of Nomenclature In 1787, Louis-Bernard Guyton de Morveau published his nomenclature recommendations in collaboration with fellow French chemists Berthollet, de Fourcroy and Lavoisier. This work however covered only what are now called inorganic compounds. With the expansion of organic chemistry in the 19th century, and a greater understanding of the structure of organic compounds, the need for a more global standardised nomenclature became more prominent. Following a series of meetings, the first of which was established in 1860 by August Kekulé, the Geneva Nomenclature of 1892 was created. Another entity called the International Association of Chemical Societies (IACS) exis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes Physical property, physical and Chemical property, chemical properties, and evaluation of Reactivity (chemistry), chemical reactivity to understand their behavior. The study of organic reactions includes the organic synthesis, chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study. The range of chemicals studied chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arene Substitution Patterns
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. ''Ortho'', ''meta'', and ''para'' substitution * In ''ortho''-substitution, two substituents occupy positions next to each other, which may be numbered 1 and 2. In the diagram, these positions are marked R and ''ortho''. * In ''meta''-substitution, the substituents occupy positions 1 and 3 (corresponding to R and ''meta'' in the diagram). * In ''para''-substitution, the substituents occupy the opposite ends (positions 1 and 4, corresponding to R and ''para'' in the diagram). The toluidines serve as an example for these three types of substitution. Synthesis Electron donating groups, for example amino, hydroxyl, alkyl, and phenyl groups tend to be ''ortho''/''para''-directors, and electron withdrawing groups such as nitro, nitrile, and ketone groups, tend to be ''meta''-directors. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Compound
A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon (i.e., are carbocycles), none of the atoms are carbon (inorganic cyclic compounds), or where both carbon and non-carbon atoms are present ( heterocyclic compounds with rings containing both carbon and non-carbon). Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resorcinol
Resorcinol (or resorcin) is a phenolic compound. It is an organic compound with the formula C6H4(OH)2. It is one of three isomeric benzenediols, the 1,3-isomer (or ''meta- (chemistry), meta''-isomer). Resorcinol crystallizes from benzene as colorless needles that are readily soluble in water, alcohol, and ether, but insoluble in chloroform and carbon disulfide. Production Resorcinol is produced in several steps from benzene, starting with dialkylation with propylene to give 1,3-Diisopropylbenzene, 1,3-diisopropylbenzene. Oxidation and Hock rearrangement of this disubstituted arene gives acetone and resorcinol. Resorcinol is a relatively inexpensive chemical. It is produced in only a very few locations around the world (as of 2010 only four commercial plants were known to be operative: in the United States, Germany, China, and Japan), and is the determining factor in the cost of Phenol formaldehyde resin, PRF adhesives. Production in the United States ended in 2017 with the cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabisulfite
A disulfite, commonly known as metabisulfite or pyrosulfite, is a chemical compound containing the ion . It is a colorless dianion that is primarily marketed in the form of sodium metabisulfite or potassium metabisulfite. When dissolved in water, these salts release the hydrogensulfite anion. These salts act equivalently to sodium hydrogensulfite or potassium hydrogensulfite. Structure In contrast to disulfate (), disulfite ion () has an unsymmetrical structure with an S-S bond. The oxidation state of the sulfur atom bonded to 3 oxygen atoms is +5 while oxidation number of other sulfur atom is +3. The anion consists of an SO2 group linked to an SO3 group, with the negative charge more localized on the SO3 end. The S–S bond length is 2.22 Å, and the "thionate" and "thionite" S–O distances are 1.46 and 1.50 Å respectively. Production Salts of disulfite ion are produced by dehydration of salts of hydrogensulfite ion (). When solutions of sodium hydrogensul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bisulfite
The bisulfite ion (IUPAC-recommended nomenclature: hydrogensulfite) is the ion . Salts containing the ion are also known as "sulfite lyes". Sodium bisulfite is used interchangeably with sodium metabisulfite (Na2S2O5). Sodium metabisulfite dissolves in water to give a solution of Na+. :Na2S2O5 + H2O → 2Na SO3 Structure The bisulfite anion exists in solution as a mixture of two tautomers. One tautomer has the proton attached to one of the three oxygen atoms. In the second tautomer the proton resides on sulfur. The S-protonated tautomer has ''C''3v symmetry. The O-protonated tautomer has only ''C''s symmetry. Reactions Tautomerization There exist two tautomers of bisulfite. They interconvert readily but can be characterized individually by various spectroscopic methods. They have been observed by 17O NMR spectroscopy: :HSO3− SO2(OH)− ''K'' = 4.9 Acid-base reactions Solutions of bisulfite are typically prepared by treatment of sulfur dioxide with aqueous bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaphosphoric Acid
In chemistry, a phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is bonded to four oxygen (O) atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these tetrahedra may be connected by shared single-bonded oxygens, forming linear or branched chains, cycles, or more complex structures. The single-bonded oxygen atoms that are not shared are completed with acidic hydrogen atoms. The general formula of a phosphoric acid is , where ''n'' is the number of phosphorus atoms and ''x'' is the number of fundamental cycles in the molecule's structure, between 0 and . Removal of protons () from ''k'' hydroxyl groups –OH leaves anions generically called phosphates (if ) or hydrogen phosphates (if ''k'' is between 1 and ), with general formula . The fully dissociated anion () has formula . The term phosphate is also used in organic chemistry for the functiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimonic Acid
Antimony is a chemical element; it has symbol Sb () and atomic number 51. A lustrous grey metal or metalloid, it is found in nature mainly as the sulfide mineral stibnite (). Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name kohl. The earliest known description of this metalloid in the West was written in 1540 by Vannoccio Biringuccio. China is the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan. The industrial methods for refining antimony from stibnite are roasting followed by reduction with carbon, or direct reduction of stibnite with iron. The most common applications for metallic antimony are in alloys with lead and tin, which have improved properties for solders, bullets, and plain bearings. It improves the rigidity of lead-alloy plates in lead–acid batteries. Antimony trioxide is a prominent additive for halogen-con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
