crystallinecrystalscrystalline solid
Evaporites such as Halite (mineral), gypsum and some limestones have been deposited from aqueous solution, mostly owing to evaporation in arid climates. Water-based ice in the form of snow, sea ice and glaciers is a very common manifestation of crystalline or polycrystalline matter on Earth. A single snowflake is a single crystal or a collection of crystals, while an ice cube is a polycrystal. Many living organisms are able to produce crystals, for example calcite and aragonite in the case of most molluscs or hydroxylapatite in the case of vertebrates. The same group of atoms can often solidify in many different ways.

Sodium chloride

NaClsaltroad salt
Sodium chloride, commonly known as salt (though sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/mol respectively, 100 g of NaCl contains 39.34 g Na and 60.66 g Cl. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form of table salt, it is commonly used as a condiment and food preservative.


In chemistry, efflorescence (which means "to flower out" in French) is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or occasionally in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt. In what has been described as "primary efflorescence," the water is the invader and the salt was already present internally. Some people describe a reverse process, where the salt is originally present externally and is then carried inside in solution, as "secondary efflorescence."

Index of chemistry articles

Pedersen Chemical bond chemical element Chemical elements named after people Chemical elements named after places Chemical engineering Chemical equilibrium chemical formula Chemical nomenclature chemical property Chemical reaction Chemical series Chemical thermodynamics Cheminformatics chemist chemistry Chemistry basic topics Chirality Chloride Chlorin chlorine Chlorite chocolate Christian B.


Svante Arrhenius put forth, in his 1884 dissertation, his explanation of the fact that solid crystalline salts dissociate into paired charged particles when dissolved, for which he would win the 1903 Nobel Prize in Chemistry. Arrhenius' explanation was that in forming a solution, the salt dissociates into Faraday's ions. Arrhenius proposed that ions formed even in the absence of an electric current. Ions in their gas-like state are highly reactive and will rapidly interact with ions of opposite charge to give neutral molecules or ionic salts.


sulfatessulphateSO 4
An example of a salt containing the group is sodium bisulfate, NaHSO 4. In dilute solutions the hydrogen sulfate ions also dissociate, forming more hydronium ions and sulfate ions. The CAS registry number for hydrogen sulfate is 14996-02-2. treating metal, metal hydroxide or metal oxide with sulfuric acid. Zn + H 2 SO 4 → ZnSO 4 + H 2. Cu(OH) 2 + H 2 SO 4 → CuSO 4 + 2 H 2 O. CdCO 3 + H 2 SO 4 → CdSO 4 + H 2 O + CO 2. oxidation of metal sulfides or sulfites. Gypsum, the natural mineral form of hydrated calcium sulfate, is used to produce plaster. About 100 million tonnes per year are used by the construction industry.

Ionic compound

ionicionic solidionic crystals
Humans have processed common salt (sodium chloride) for over 8000 years, using it first as a food seasoning and preservative, and now also in manufacturing, agriculture, water conditioning, for de-icing roads, and many other uses. Many ionic compounds are so widely used in society that they go by common names unrelated to their chemical identity. Examples of this include borax, calomel, milk of magnesia, muriatic acid, oil of vitriol, saltpeter, and slaked lime. Soluble ionic compounds like salt can easily be dissolved to provide electrolyte solutions. This is a simple way to control the concentration and ionic strength.

Chemical reaction

reactionchemical reactionsreactions
Chemical reaction. Substrate. Reagent. Catalyst. Product. Chemical reaction model. Chemist. Chemistry. Limiting reagent. List of organic reactions. Microscopic reversibility. Organic reaction. Reaction progress kinetic analysis. Reversible reaction. Combustion. Mass balance.

Calcium sulfate

calcium sulphateCaSO 4 Drierite
Gypsum. Gypsum plaster. Phosphogypsum. Selenite (mineral). Flue-gas desulfurization. International Chemical Satefy Card 1215. NIOSH Pocket Guide to Chemical Hazards.


solidsssolid state
The chemical pulping processes use a combination of high temperature and alkaline (kraft) or acidic (sulfite) chemicals to break the chemical bonds of the lignin before burning it out. One important property of carbon in organic chemistry is that it can form certain compounds, the individual molecules of which are capable of attaching themselves to one another, thereby forming a chain or a network. The process is called polymerization and the chains or networks polymers, while the source compound is a monomer.


OHhydroxide ionOH −
Hydroxide is a diatomic anion with chemical formula OH −. It consists of an oxygen and hydrogen atom held together by a covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation (H + ), making the parent compound an acid.

Polyatomic ion

molecular ionpolyatomicpolyatomic anion
Its chemical formula is OH-. An ammonium ion consists of one nitrogen atom and four hydrogen atoms: it has a charge of +1, and its chemical formula is NH4+. Polyatomic ions are often useful in the context of acid-base chemistry or in the formation of salts. A polyatomic ion can often be considered as the conjugate acid or base of a neutral molecule. For example, the conjugate base of sulfuric acid (H 2 SO 4 ) is the polyatomic hydrogen sulfate anion (HSO4-). The removal of another hydrogen ion yields the sulfate anion (SO4(2-)). There are two "rules" that can be used for learning the nomenclature of polyatomic anions.


molecularmoleculesmolecular structure
In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds with no presence of any definable molecule, nor any of the regularity of repeating units that characterizes crystals. The science of molecules is called molecular chemistry or molecular physics, depending on whether the focus is on chemistry or physics. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with the laws governing their structure and properties. In practice, however, this distinction is vague.

Ancient Egypt

EgyptEgyptianAncient Egyptian
Embalmers used salts from the Wadi Natrun for mummification, which also provided the gypsum needed to make plaster. Ore-bearing rock formations were found in distant, inhospitable wadis in the eastern desert and the Sinai, requiring large, state-controlled expeditions to obtain natural resources found there. There were extensive gold mines in Nubia, and one of the first maps known is of a gold mine in this region. The Wadi Hammamat was a notable source of granite, greywacke, and gold. Flint was the first mineral collected and used to make tools, and flint handaxes are the earliest pieces of evidence of habitation in the Nile valley.

Organic chemistry

organicorganic chemistorganic chemical
Organic chemistry is a subdiscipline of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Study of structure determines their chemical composition and formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study.


metalsmetal ionsmetal ion
In chemistry, two elements that would otherwise qualify (in physics) as brittle metals—arsenic and antimony—are commonly instead recognised as metalloids, on account of their predominately non-metallic chemistry. Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved. In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than the lightest two, hydrogen and helium, and not just traditional metals.


phosphatesphosphate groupinorganic phosphate
A Phosphate is a chemical derivative of phosphoric acid. The phosphate ion is an inorganic chemical, the conjugate base that can form many different salts. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Of the various phosphoric acids and phosphates, organic phosphates are important in biochemistry and biogeochemistry (and, consequently, in ecology), and inorganic phosphates are mined to obtain phosphorus for use in agriculture and industry. At elevated temperatures in the solid state, phosphates can condense to form pyrophosphates.


FeFe 2+ Fe(III)
The ferrous halides typically arise from treating iron metal with the corresponding hydrohalic acid to give the corresponding hydrated salts.


CaCa 2+ calcium ions
In 1787, Antoine Lavoisier suspected that lime might be an oxide of a fundamental chemical element. In his table of the elements, Lavoisier listed five "salifiable earths" (i.e., ores that could be made to react with acids to produce salts (salis = salt, in Latin): chaux (calcium oxide), magnésie (magnesia, magnesium oxide), baryte (barium sulfate), alumine (alumina, aluminium oxide), and silice (silica, silicon dioxide)).

Base (chemistry)

In chemistry, bases are substances that, in aqueous solution, release hydroxide (OH − ) ions, are slippery to the touch, can taste bitter if an alkali, change the color of indicators (e.g., turn red litmus paper blue), react with acids to form salts, promote certain chemical reactions (base catalysis), accept protons from any proton donor or contain completely or partially displaceable OH − ions. Examples of bases are the hydroxides of the alkali metals and the alkaline earth metals (NaOH, Ca(OH) 2, etc.—see alkali hydroxide and alkaline earth hydroxide).


table saltsalt productioncommon salt
Salt is a mineral consisting primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in seawater, where it is the main mineral constituent. The open ocean has about 35 g of solids per liter of sea water, a salinity of 3.5%. Salt is essential for life in general, and saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation.


Zumdahl, Chemistry, 4th Edition. Ebbing, D.D., & Gammon, S. D. (2005). General chemistry (8th ed.). Boston, MA: Houghton Mifflin. ISBN: 0-618-51177-6. Pavia, D.L., Lampman, G.M., & Kriz, G.S. (2004). Organic chemistry volume 1: Organic chemistry 351. Mason, OH: Cenage Learning. ISBN: 0-7593-4727-1.

Sulfuric acid

sulphuric acidsulfuricH 2 SO 4
Later refinements to the lead chamber process by French chemist Joseph Louis Gay-Lussac and British chemist John Glover improved concentration to 78%. However, the manufacture of some dyes and other chemical processes require a more concentrated product. Throughout the 18th century, this could only be made by dry distilling minerals in a technique similar to the original alchemical processes.


In industrial chemistry, distillation is a unit operation of practically universal importance, but it is a physical separation process, not a chemical reaction. Distillation has many applications. For example: An installation used for distillation, especially of distilled beverages, is called a distillery. The distillation equipment at a distillery is a still. In 1975 Paolo Rovesti (1902–1983) a chemist and pharmacist discovered a terracotta distillation apparatus in the Indus valley in West Pakistan which dates from around 3000 BC. Early evidence of distillation was found on Akkadian tablets dated circa 1200 BC describing perfumery operations.