Chemistry

Sulfite (SO3^2−): composition, properties, uses and health considerations Sulfite Summary of the sulfite ion (SO3^2−): structure, chemistry, common salts, industrial and food uses, environmental role, health effects and regulatory concerns.

Sulfone (organic functional group) Sulfone Sulfones are organic compounds with a sulfur atom bonded to two oxygens (sulfur(VI) dioxide) and two carbon groups; they are stable, polar, and find use in synthesis, materials, an…

Sulfoxide: structure, properties, synthesis and uses Sulfoxide Sulfoxides are organosulfur compounds with the general formula R–S(=O)–R'. This article explains their structure, stereochemistry, preparation, common uses (notably DMSO) and safet…

Sulfur (element S) Sulfur Sulfur is a nonmetal chemical element (symbol S, atomic number 16) known for its yellow crystals, multiple allotropes, role in industry and biology, and involvement in the global s…

Sulfur dichloride (SCl2) Sulfur dichloride Sulfur dichloride, SCl2, is a covalent sulfur halide used as an intermediate in chlorosulfur chemistry. It is a reactive, corrosive liquid that hydrolyzes in water and is handled u…

Sulfur dioxide (SO2) Sulfur dioxide Sulfur dioxide is a colorless, pungent gas (SO2) produced naturally and by industry. It is used in chemical manufacture and food preservation, and it influences air quality and aci…

Sulfur hexafluoride (SF6): properties, uses, and environmental concerns Sulfur hexafluoride Sulfur hexafluoride (SF6) is a colourless, inert gas used as an electrical insulator and tracer. It is chemically stable but a very potent, long‑lived greenhouse gas, prompting alt…

Sulfur nitride Class of binary sulfur–nitrogen compounds (notably S4N4, S2N2 and polymeric (SN)x) valued for distinctive cage structures, chemical reactivity and the conductive polymer polythiazy…

Sulfur oxide (SOx): forms, properties, sources and impacts Sulfur oxide Overview of sulfur oxides: major chemical forms, physical and chemical properties, natural and man-made sources, environmental and health effects, industrial uses, and mitigation m…

Sulfur tetrafluoride (SF4) Sulfur tetrafluoride Sulfur tetrafluoride (SF4) is a reactive inorganic gas used as a fluorinating reagent in organic synthesis; it has a see-saw molecular shape and must be handled under inert, dry co…

Sulfur trioxide (SO3): properties, production, uses and hazards Sulfur trioxide Sulfur trioxide (SO3) is the anhydride of sulfuric acid. This article covers its structure and forms, industrial production, core reactions, uses in chemistry and major safety and…

Sulfuric acid: properties, production, uses and safety Sulfuric acid Sulfuric acid (H2SO4) is a dense, highly corrosive strong acid used industrially and in laboratories. This article summarizes its chemistry, history, major applications, forms, and…

Sulfurous acid (H2SO3): properties, formation, and uses Sulfurous acid Sulfurous acid (H2SO3) is the aqueous form of dissolved sulfur dioxide. It is a weak, partly dissociated acid that yields sulfite species, acts as a mild reducing agent, and is imp…

Sulfate (SO4^2−): structure, occurrence, and uses Sulphate Sulfate (SO4^2−) is the divalent anion derived from sulfuric acid. This article summarizes its structure, common salts, natural occurrence, industrial uses, environmental roles, an…

Sulphide (sulfide): anions, thioethers, minerals and uses Sulphide Sulphide refers to the sulfur anion S2− and to organic thioethers; it appears in gases like H2S, in metal sulfide minerals, and in many industrial and biological processes.

Super glue (cyanoacrylate) — properties, uses, history and safety Super glue Overview of cyanoacrylate adhesives (commonly called super glue): how they work, typical properties, common uses, safety considerations, and brief history of development and medica…

Superacid — acids stronger than sulfuric acid Superacid A superacid is an acid whose protonating ability exceeds that of 100% sulfuric acid. These extremely strong acids are used in research and industry to protonate resistant substrate…

Superalloy: high-temperature, corrosion-resistant metal alloys for demanding applications Superalloy Superalloys are high-performance metal alloys engineered for strength, creep resistance and oxidation resistance at elevated temperatures; widely used in aerospace, power generatio…

Supersaturation State in which a solution or vapor contains more solute or vapor than its equilibrium solubility, producing a metastable condition that can trigger crystallization, precipitation,…

Supramolecular Chemistry: Principles, History, and Applications Supramolecular chemistry Study of chemical systems formed by non-covalent interactions between molecules; covers molecular recognition, self-assembly, biological inspiration, tools, applications, and notab…

Surface chemistry: reactions and phenomena at interfaces Surface chemistry Study of chemical phenomena occurring at surfaces and interfaces, including adsorption, catalysis, corrosion, wetting, and analytical techniques used to probe surface processes.

Surface energy: origins, measurement, and applications Surface energy Surface energy is the excess free energy at an interface caused by molecular imbalance. It underlies surface tension, wetting, capillarity and is central to coatings, detergents, m…

Surfactant: function, structure, types and common uses Surfactant A surfactant is a substance that reduces the surface tension of a liquid and alters interactions between liquids, solids and gases; widely used as detergents, emulsifiers, wetting…

Suspension (chemistry): particulate dispersions in fluids Suspension (chemistry) A suspension is a heterogeneous mixture of solid particles dispersed in a fluid that do not dissolve. This article explains properties, stability factors, related systems, examples…

Synthetic cannabis (K2, Spice) — overview, effects, and risks Synthetic cannabis Man-made chemical mixtures sold as K2 or Spice that are sprayed onto plant material; they act on the same brain receptors as THC but are chemically different and carry unpredictabl…

Table salt (sodium chloride) Table salt Table salt is crystalline sodium chloride used for seasoning, preservation, and industrial chemistry. It occurs naturally as rock salt and in seawater and is produced by evaporatio…

Tabun (GA): the first G-series nerve agent Tabun Tabun (GA) is an organophosphorus nerve agent discovered in the 1930s. Highly toxic and banned under modern arms-control treaties, it inhibits acetylcholinesterase and causes rapid…

Tannin: plant polyphenols that bind proteins and affect flavor Tannin Tannins are a diverse group of plant polyphenols that bind proteins, produce astringency and bitterness, and are important in food, beverages, leather processing and ecology.

Tantalum Tantalum is a dense, corrosion‑resistant transition metal (symbol Ta, atomic number 73) used in electronics, alloys, medical implants and chemical equipment due to its stability an…

Tar: production, properties, uses, and risks Tar Tar is a dark, viscous organic residue formed by heating organic matter. This article explains its origins, composition, production methods, common uses, and health and environment…

Tarnish: formation, types, effects and prevention Tarnish Tarnish is a thin, often discolored film formed on certain metals by chemical reactions with air or pollutants. This article explains how tarnish forms, common types, its uses and…

Taurine: roles, synthesis, dietary sources, and physiological functions Taurine Taurine explained: its chemistry, synthesis from cysteine, dietary sources (meat, fish), and physiological roles in heart, muscle, retina, bile composition, osmoregulation and cell…

Taxane (plant-derived anti-cancer compounds) Taxane Taxanes are naturally occurring diterpenoid compounds from yew (Taxus) trees that stabilize microtubules and are widely used as chemotherapeutic agents such as paclitaxel and docet…

Tear gas (riot-control chemical agents) Tear gas Overview of tear gas agents used for riot control: composition, effects, delivery methods, historical and legal context, health risks, first aid, and policy considerations.

Technetium Technetium (Tc, atomic number 43) is a radioactive, silvery-gray transition metal, notable as the lightest element with no stable isotopes and for its medical and industrial applic…

Tellurate (tellurium oxoanions) Tellurate Tellurate refers to oxoanions and salts of tellurium in the +6 oxidation state. They are oxidizing anions related to selenates and form salts and acids such as sodium tellurate and…

Telluric acid (H6TeO6): properties, structure, preparation and uses Telluric acid Telluric acid, H6TeO6, is a weak, oxygenated acid of tellurium that forms tellurate salts; this article summarizes its structure, reactions, preparation, uses and distinguishing fe…

Telluride (Te2−): the tellurium(−II) ion and its compounds Telluride Telluride is the tellurium anion Te2− and its salts. It appears in strongly basic solutions and in minerals, is a strong reducing agent, and protonates to HTe− and hydrogen telluri…

Tellurite (ion and mineral) Tellurite Overview of the tellurite ion (TeO3 2−), its chemistry, preparation, and the mineral tellurite (TeO2), including properties, uses, and distinctions.

Tellurium — element Te (atomic number 52) Tellurium Tellurium is a rare metalloid element (symbol Te, atomic number 52) in the chalcogen group. It has several naturally occurring isotopes, semiconducting properties, and uses in allo…

Tellurium trioxide (TeO3) Tellurium trioxide An overview of tellurium trioxide, TeO3: its composition, structures, preparation, reactivity as the anhydride of telluric acid, uses, and safety considerations.

Tellurium(II) bromide (TeBr2): properties, structure, and uses Tellurium(II) bromide Tellurium(II) bromide (TeBr2) is an inorganic tellurium halide in which tellurium is in the +2 oxidation state. It is a less common, reactive compound used primarily in research an…

Tellurium(II) chloride (tellurium dichloride) Tellurium(II) chloride An overview of tellurium(II) chloride (TeCl2): composition, bonding and oxidation state, preparation and reactivity, comparison with other tellurium halides, uses in research, and…

Tellurium(IV) bromide (tellurium tetrabromide) Tellurium(IV) bromide An overview of tellurium(IV) bromide (TeBr4), covering composition, structure, preparation, properties, common uses, and safety considerations for this inorganic halide.

Tellurium(IV) chloride (tellurium tetrachloride) Tellurium(IV) chloride Tellurium(IV) chloride (TeCl4) is a covalent inorganic chloride of tellurium in the +4 oxidation state. It is a reactive, moisture-sensitive compound used in synthesis and as a chl…

Tellurium(IV) fluoride (tellurium tetrafluoride) Tellurium(IV) fluoride Tellurium(IV) fluoride (TeF4) is an inorganic fluoride of tellurium in oxidation state +4. It is a reactive, moisture-sensitive solid used in specialized fluorination chemistry and…

Tellurium(IV) oxide (tellurium dioxide, TeO2) Tellurium(IV) oxide Tellurium(IV) oxide (TeO2) is a white crystalline inorganic oxide of tellurium in the +4 state. It appears in two polymorphs, is used in optics and glass, and is chemically amphote…

Tellurium(VI) fluoride (tellurium hexafluoride) Tellurium(VI) fluoride Tellurium(VI) fluoride (TeF6) is a volatile inorganic molecule with octahedral geometry. It hydrolyzes to tellurium oxoacids and HF; its uses are mainly research-oriented and it re…