An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
The chalcogens are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" is derived from a combination of the Greek word khalkos (χαλκός) principally meaning copper, and the Latinized Greek word genēs, meaning born or produced.
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles.
The nitronium ion, [NO2]+, is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion [NH4]+. It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule NO2, or the protonation of nitric acid HNO3.
Sulfur (also spelled sulphur in British English) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.
Cysteine is a semiessential proteinogenic amino acid with the formula HOOC−CH(−NH2)−CH2−SH. The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. Cysteine is chiral, but both D and L-cysteine are found in nature. L‑Cysteine is a protein monomer in all biota, and D-cysteine acts as a signaling molecule in mammalian nervous systems. Cysteine is named after its discovery in urine, which comes from the urinary bladder or cyst, from Greek κύστη kýsti, "bladder".
In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".
The sulfate or sulphate ion is a polyatomic anion with the empirical formula SO2−4. Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.
The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl.
Sulfide (also sulphide in British English ) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.
Sulfur trioxide (alternative spelling sulphur trioxide) is the chemical compound with the formula SO3. It has been described as "unquestionably the most [economically] important sulfur oxide". It is prepared on an industrial scale as a precursor to sulfuric acid.
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols and nitric acid. The difference between the resulting molecular structures of nitro compounds and nitrates is that the nitrogen atom in nitro compounds is directly bonded to a non-oxygen atom, whereas in nitrate esters, the nitrogen is bonded to an oxygen atom that in turn usually is bonded to a carbon atom.
A peroxy acid is an acid which contains an acidic −OOH group. The two main classes are those derived from conventional mineral acids, especially sulfuric acid, and the peroxy derivatives of organic carboxylic acids. They are generally strong oxidizers.
Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature is abound with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
Disulfuric acid (alternative spelling disulphuric acid) or pyrosulfuric acid (alternative spelling pyrosulphuric acid), also named oleum, is a sulfur oxoacid. It is a major constituent of fuming sulfuric acid, oleum, and this is how most chemists encounter it. As confirmed by X-ray crystallography, the molecule consists of a pair of SO2(OH) groups joined by an oxide.
An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H+ cation and the anion of the acid.
Chemical Entities of Biological Interest, also known as ChEBI, is a chemical database and ontology of molecular entities focused on 'small' chemical compounds, that is part of the Open Biomedical Ontologies (OBO) effort at the European Bioinformatics Institute (EBI). The term "molecular entity" refers to any "constitutionally or isotopically distinct atom, molecule, ion, ion pair, radical, radical ion, complex, conformer, etc., identifiable as a separately distinguishable entity". The molecular entities in question are either products of nature or synthetic products which have potential bioactivity. Molecules directly encoded by the genome, such as nucleic acids, proteins and peptides derived from proteins by proteolytic cleavage, are not as a rule included in ChEBI.
The dithionate (or metabisulfate) anion, S
2O2−
6, is a sulfur oxoanion derived from dithionic acid, H2S2O6. Its chemical formula is sometimes written in a semistructural format, as [O3SSO3]2−. It is the first member of the polythionates.
Hydrogen chalcogenides are binary compounds of hydrogen with chalcogen atoms. Water, the first chemical compound in this series, contains one oxygen atom and two hydrogen atoms, and is the most common compound on the Earth's surface.
In chemistry, a fluoroanion or fluorometallate anion is a polyatomic anion that contains one or more fluorine atoms. The ions and salts form from them are also known as complex fluorides. They can occur in salts, or in solution, but seldom as pure acids. Fluoroanions often contain elements in higher oxidation states. They mostly can be considered as fluorometallates, which are a subclass of halometallates.
