Chemistry

Silver(I) sulfide (Ag2S) Silver(I) sulfide Silver(I) sulfide, Ag2S, is the black sulfide of silver. It is a naturally occurring mineral and a narrow-gap semiconductor that forms by tarnishing of silver and has applications…

Silver(II) fluoride (AgF2): properties, uses and safety Silver(II) fluoride Silver(II) fluoride (AgF2) is a rare silver compound and a powerful oxidizing and fluorinating agent used in specialized chemical synthesis; it requires extreme caution due to corr…

Simplified molecular-input line-entry specification (SMILES) Simplified molecular input line entry specification SMILES is a compact ASCII notation for describing molecular structures. It encodes atoms, bonds, branches, rings and stereochemistry for storage, searching and graphical reconstruc…

Sintering: Powder Consolidation and Solid-State Densification Sintering Sintering joins powdered materials into a coherent solid by heating below melting point. Covers mechanisms, process variants, materials, applications, history and practical distinc…

Slag (byproduct of iron and steelmaking) Slag An overview of slag: its formation during metalmaking, composition and types, industrial uses (cement, concrete, mineral wool, aggregates), environmental aspects and historical dev…

Slurry: Definition, Properties, History and Uses Slurry A slurry is a flowable mixture of solid particles suspended in a liquid. This article explains composition, physical behavior, common applications, handling challenges and distinct…

Smelting: extracting metals from ores by heat and chemical reduction Smelting Smelting is the high-temperature process that separates metals from ores by chemical reduction and melting. This article explains principles, methods, historical background, enviro…

Smoke: composition, hazards, uses, and distinguishing features Smoke An overview of smoke: what it is, what it contains, health and environmental effects, historical and cultural uses, safety advice, and how smoke differs from fumes or vapors.

SN1 reaction — unimolecular nucleophilic substitution SN1 reaction SN1 is a two-step unimolecular nucleophilic substitution in which the substrate ionizes to a carbocation. This entry explains mechanism, kinetics, stereochemistry, factors influenc…

SN2 reaction (bimolecular nucleophilic substitution) SN2 reaction One-step nucleophilic substitution in which a nucleophile displaces a leaving group by simultaneous bond formation and bond breaking; rate depends on both reactants.

Soap: composition, history, and practical uses Soap Overview of soap as a cleansing compound: how it’s made, how it works, its history from antiquity, common types, uses and environmental considerations.

Soda: chemical meanings, products, and everyday uses Soda Survey of 'soda' as a chemical term and a common name for foods and drinks; covers key sodium compounds, industrial and culinary uses, history, and distinctions like baking soda vs…

Sodium (Na): properties, uses, occurrence and history Sodium Sodium is a soft, highly reactive alkali metal (Na, atomic number 11) essential to industry, chemistry and biological systems. This entry summarizes its properties, common compound…

Sodium acetate (CH3COONa) Sodium acetate Sodium acetate is the sodium salt of acetic acid, used in laboratories, industry, food, and reusable heating pads. It occurs as anhydrous and trihydrate forms and is prepared by ne…

Sodium amide (NaNH2): properties, synthesis, uses and safety Sodium amide Sodium amide (NaNH2) is a white ionic solid containing Na+ and NH2−. A very strong base used in organic synthesis and industrial chemistry; it is highly reactive toward water and m…

Sodium arsenite Sodium arsenite (NaAsO2) is an inorganic arsenic salt used in laboratory research and formerly in industry; it is highly toxic and handled under strict safety controls.

Sodium azide (NaN3): properties, uses, and safety Sodium azide Sodium azide (NaN3) is an inorganic azide salt used as an azide source and formerly in vehicle airbags. It is highly toxic and potentially explosive; this article summarizes its pr…

Sodium bicarbonate (baking soda): properties, uses, and safety Sodium bicarbonate Sodium bicarbonate (baking soda) is a common, mildly alkaline compound used in cooking, medicine, cleaning and industry. This entry summarizes its chemistry, uses, manufacture, and…

Sodium bismuthate (NaBiO3) Sodium bismuthate Sodium bismuthate (NaBiO3) is an inorganic bismuth(V) oxide salt and a powerful oxidizing reagent, used chiefly in analytical chemistry and selected oxidative preparations.

Sodium bisulfate (sodium hydrogen sulfate) Sodium bisulfate Sodium bisulfate (NaHSO4) is a white, water-soluble acidic salt used industrially and domestically to lower pH. It is produced by partial neutralization of sulfuric acid or by reac…

Sodium bromate Sodium bromate (NaBrO3) is a colorless inorganic oxidizing salt used in chemical synthesis and industry; it is a strong oxidant and a regulated toxicant with safety restrictions.

Sodium bromide (NaBr): properties, uses, history and safety Sodium bromide Sodium bromide (NaBr) is an ionic inorganic salt used as a laboratory reagent and historical medicine. This article outlines its properties, preparation, applications, and safety c…

Sodium carbonate (soda ash, washing soda) Sodium carbonate An overview of sodium carbonate (Na2CO3): composition, properties, production methods, common uses in industry and home, historical context, and safety considerations.

Sodium chlorate: properties, production, uses and safety Sodium chlorate Sodium chlorate (NaClO3) is a white crystalline oxidizer produced by electrolyzing brine. It has industrial uses (herbicide, pulp bleaching, chemical intermediate) and significant…

Sodium chlorite: properties, uses, and safety overview Sodium chlorite An accessible summary of sodium chlorite (NaClO2): its chemistry, common applications, handling precautions, and how it differs from related chlorine oxyanions.

Sodium chromate (Na2CrO4): properties, production, uses and safety Sodium chromate Sodium chromate (Na2CrO4) is a bright yellow, water‑soluble chromate salt. It is a strong oxidizer and a source of toxic Cr(VI) ions; used in industry and laboratories with strict…

Sodium dichromate (Na2Cr2O7) Sodium dichromate Inorganic orange crystalline salt used as an oxidizing reagent and industrial intermediate. Highly soluble and toxic; contains hexavalent chromium and is regulated for health and e…

Sodium fluoride (NaF) — properties, production, uses, and safety Sodium fluoride Sodium fluoride (NaF) is an inorganic ionic compound used in dental care and industry. This article summarizes its properties, manufacture, applications, history, and safety consid…

Sodium hydroxide (caustic soda) — properties, uses, and safety Sodium hydroxide Sodium hydroxide (NaOH), commonly called caustic soda or lye, is a strong inorganic base used in industry and households. This article covers its properties, manufacture, applicati…

Sodium hypochlorite Sodium hypochlorite (NaClO) is a common liquid bleach and disinfectant. It is an alkaline, greenish solution that acts as a strong oxidizer and is widely used for sanitation, water…

Sodium hypophosphite (NaH2PO2) Sodium hypophosphite Sodium hypophosphite, NaH2PO2, is a water‑soluble salt of hypophosphorous acid used industrially as a reducing agent and in electroless nickel plating; it is handled with care beca…

Sodium iodate (NaIO3) Sodium iodate Sodium iodate is the sodium salt of iodic acid, an inorganic oxidizing compound used as a laboratory reagent and stable source of iodine; it is a white, water-soluble crystalline s…

Sodium iodide (NaI): properties, history, uses and safety Sodium iodide Sodium iodide (NaI) is an inorganic ionic salt used in medicine, chemistry and radiation detection. This article covers its composition, behavior, common applications and storage/s…

Sodium manganate (Na2MnO4) Sodium manganate An inorganic sodium salt of the manganate ion (MnO4(2−)); a bright green, water-soluble compound used mainly as a laboratory intermediate and oxidizing agent.

Sodium monofluoroacetate (sodium fluoroacetate): properties, occurrence, uses, and risks Sodium monofluoroacetate Overview of sodium monofluoroacetate (1080): chemical nature, natural occurrence, mechanism of toxicity, applications in pest control and research, safety, and regulatory issues.

Sodium nitrate (NaNO3): properties, uses, and history Sodium nitrate Sodium nitrate (NaNO3), also called Chile saltpeter or caliche, is a widely used inorganic salt. This article covers its composition, properties, historical mining, industrial prod…

Sodium nitrite (NaNO2): properties, uses and safety Sodium nitrite Sodium nitrite is an inorganic salt used in food curing, industry and synthesis. It acts as a nitrite source, has oxidizing properties, and requires careful handling due to toxicit…

Sodium periodate (NaIO4 and Na5IO6) Sodium periodate Inorganic oxidizing salts of iodine in its highest oxidation state. Occurs as metaperiodate (NaIO4) and orthoperiodate (Na5IO6); used for selective oxidative cleavage of vicinal di…

Sodium permanganate (NaMnO4) Sodium permanganate Sodium permanganate (NaMnO4) is a water‑soluble permanganate salt and strong oxidizing agent used in chemistry, water treatment and organic synthesis; it is similar to potassium pe…

Sodium phosphate — salts, properties, uses and safety Sodium phosphate Overview of sodium phosphate salts, common forms (mono-, di-, tri-sodium), chemical behavior, applications in food, industry and medicine, and environmental and health consideratio…

Sodium phosphide (Na3P) Sodium phosphide Inorganic sodium phosphide (Na3P) is a dark, air‑sensitive ionic solid that hydrolyzes to phosphine. It is used as a reagent and intermediate; handling requires strict safety preca…

Sodium phosphite An inorganic salt derived from phosphorous acid, commonly encountered as disodium hydrogen phosphite; used in specialty chemistry, agriculture, and as a reducing agent.

Sodium selenate Inorganic sodium salt Na2SeO4 containing selenate (Se(VI)) ions. Water-soluble crystalline compound used as a laboratory source of selenium; biologically active and potentially tox…

Sodium selenide (Na2Se): properties, preparation, uses and safety Sodium selenide Sodium selenide (Na2Se) is an ionic selenide salt used in synthesis as a source of Se2−. It is a reactive, moisture-sensitive solid that releases toxic H2Se on hydrolysis and requi…

Sodium selenite (Na2SeO3): properties, uses and safety Sodium selenite Inorganic salt sodium selenite (Na2SeO3), a water-soluble selenium(IV) compound used in industry, research, and supplements; covers structure, preparation, applications, toxicity a…

Sodium sulfate (Glauber's salt): properties, production, and uses Sodium sulfate Overview of sodium sulfate (Na2SO4), its forms, physical and chemical properties, industrial and historical uses, methods of production, and safety/environmental considerations.

Sodium sulfite (Na2SO3) Sodium sulfite Inorganic sodium salt used as a mild reducing agent, preservative and dechlorinator. Forms anhydrous and hydrated crystals, reacts with acids to release sulfur dioxide and oxidizes…

Sodium telluride (Na2Te) Sodium telluride Sodium telluride (Na2Te) is an inorganic salt containing Na+ and telluride (Te2−). It is a reducing agent used as a telluride source in synthesis, sensitive to air and moisture and…