3D model (JSmol)
|Molar mass||197.34 g/mol|
|Melting point|| 811 °C (1,492 °F; 1,084 K) |
|Boiling point|| 1,450 °C (2,640 °F; 1,720 K) |
decomposes from 1360 °C
|16 mg/L (8.8°C)|
22 mg/L (18 °C)
24 mg/L (20 °C)
24 mg/L (24.2 °C)
Solubility product (Ksp)
|Solubility||decomposes in acid|
insoluble in methanol
Refractive index (nD)
Heat capacity (C)
Std enthalpy of
Gibbs free energy (ΔfG˚)
|Safety data sheet||ICSC 0777|
|GHS signal word||Warning|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|418 mg/kg, oral (rat)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Witherite crystallizes in the orthorhombic system. The crystals are invariably twinned together in groups of three, giving rise to pseudo-hexagonal forms somewhat resembling bipyramidal crystals of quartz, the faces are usually rough and striated horizontally. It transforms into an hexagonal phase at 1084 K that changes into a cubic phase at 1254 K.
The mineral is named after William Withering, who in 1784 recognized it to be chemically distinct from barytes. It occurs in veins of lead ore at Hexham in Northumberland, Alston in Cumbria, Anglezarke, near Chorley in Lancashire and a few other localities. Witherite is readily altered to barium sulfate by the action of water containing calcium sulfate in solution and crystals are therefore frequently encrusted with barytes. It is the chief source of barium salts and is mined in considerable amounts in Northumberland. It is used for the preparation of rat poison, in the manufacture of glass and porcelain, and formerly for refining sugar. It is also used for controlling the chromate to sulfate ratio in chromium electroplating baths.
In the soda ash process, solid or dissolved sodium carbonate is added to barium sulfide solution, and the barium carbonate precipitate is filtered, washed and dried.
Barium carbonate is widely used in the ceramics industry as an ingredient in glazes. It acts as a flux, a matting and crystallizing agent and combines with certain colouring oxides to produce unique colours not easily attainable by other means. Its use is somewhat controversial since some claim that it can leach from glazes into food and drink. To provide a safe means of use, BaO is often used in fritted form.
In chemistry, an alkali (; from Arabic: al-qaly "ashes of the saltwort") is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is commonly, and alkalescent less often, used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Its hydroxide, known in pre-modern times as baryta, does not occur as a mineral, but can be prepared by heating barium carbonate.
The most common naturally occurring minerals of barium are barite (now called baryte) (barium sulfate, BaSO4) and witherite (barium carbonate, BaCO3), both insoluble in water. The name barium originates from the alchemical derivative "baryta", from Greek βαρύς (barys), meaning "heavy." Baric is the adjectival form of barium. Barium was identified as a new element in 1774, but not reduced to a metal until 1808 with the advent of electrolysis.
Barium has few industrial applications. Historically, it was used as a getter for vacuum tubes and in oxide form as the emissive coating on indirectly heated cathodes. It is a component of YBCO (high-temperature superconductors) and electroceramics, and is added to steel and cast iron to reduce the size of carbon grains within the microstructure. Barium compounds are added to fireworks to impart a green color. Barium sulfate is used as an insoluble additive to oil well drilling fluid, as well as in a purer form, as X-ray radiocontrast agents for imaging the human gastrointestinal tract. The soluble barium ion and soluble compounds are poisonous, and have been used as rodenticides.Barium acetate
Barium acetate (Ba(C2H3O2)2) is the salt of barium(II) and acetic acid.Barium bromide
Barium bromide is the chemical compound with the formula BaBr2. Like barium chloride, it dissolves well in water and is toxic.Barium chlorate
Barium chlorate, Ba(ClO3)2, is a white crystalline solid, the barium salt of chloric acid. It is an irritant and toxic, as are all soluble barium compounds. It is sometimes used in pyrotechnics to produce a green color. It also finds use in the production of chloric acid.Barium chloride
Barium chloride is the inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like most other barium salts, it is white, toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting first to the dihydrate BaCl2(H2O)2. It has limited use in the laboratory and industry.Barium hydroxide
Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2(H2O)x. The monohydrate (x =1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form.Barium metaphosphate
Barium metaphosphate is an inorganic substance with the molecular formula Ba(PO3)2. It is a colourless solid that is insoluble in water, though is soluble in acidic solutions through "slow dissolution". X-ray crystallography shows that this material is composed of Ba2+ cations attached to a polyphosphate ((PO3−)n) anion. A number of hydrated forms are known which are actually cyclic metaphosphates, Ba2(P4O12)·3.5H2O, Ba3(P3O9)2·6H2O.Barium nitrate
Barium nitrate is the inorganic compound with the chemical formula Ba(NO3)2. It, like most barium salts, is colorless, toxic, and water-soluble. It burns with a green flame and is an oxidizer; the compound is commonly used in pyrotechnics.Barium oxide
Barium oxide, BaO, is a white hygroscopic non-flammable compound. It has a cubic structure and is used in cathode ray tubes, crown glass, and catalysts. It is harmful to human skin and if swallowed in large quantity causes irritation. Excessive quantities of barium oxide may lead to death.
It is prepared by heating barium carbonate with coke, carbon black or tar or by thermal decomposition of barium nitrate.Barium perchlorate
Barium perchlorate is a powerful oxidizing agent, with the formula Ba(ClO4)2. It is used in the pyrotechnic industry.
Barium perchlorate decomposes at 505 °C.Brin process
Brin process is a now-obsolete industrial scale production process for oxygen. In this process barium oxide reacts at 500–600 °C with air to form barium peroxide which decomposes at above 800 °C by releasing oxygen.
2 BaO + O2 ⇌ 2 BaO2The reaction was discovered by Joseph-Louis Gay-Lussac and Louis-Jacques Thenard in 1811 and Jean-Baptiste Boussingault tried to use this reaction to establish a process to produce oxygen in 1852. The process worked only for a few cycles and then became inefficient. Two students of Boussingault, Quentin and Arthur Leon Brin, discovered that traces of carbon dioxide formed barium carbonate. Removing the carbon dioxide with sodium hydroxide solved this problem. In 1884 they opened a factory producing oxygen by their improved process. In the commercial process, oxygen capture and release was controlled by pressure rather than temperature, with oxygen being captured at high pressure and released at low pressure. This allowed a faster change between the capture and release phases, which would last one to two hours.
The company was first named after the two brothers Brins Oxygen Company in 1906 it was renamed Britisch Oxygen Company.One major application of the oxygen was the use for limelight. Before the end of the 19th century electrolysis of water and fractional distillation of liquefied air became economically cheaper methods to produce oxygen and the process slowly faded out.Carburizing
Carburizing, carburising (chiefly British English), or carburization is a heat treatment process in which iron or steel absorbs carbon while the metal is heated in the presence of a carbon-bearing material, such as charcoal or carbon monoxide. The intent is to make the metal harder. Depending on the amount of time and temperature, the affected area can vary in carbon content. Longer carburizing times and higher temperatures typically increase the depth of carbon diffusion. When the iron or steel is cooled rapidly by quenching, the higher carbon content on the outer surface becomes hard due to the transformation from austenite to martensite, while the core remains soft and tough as a ferritic and/or pearlite microstructure.This manufacturing process can be characterized by the following key points: It is applied to low-carbon workpieces; workpieces are in contact with a high-carbon gas, liquid or solid; it produces a hard workpiece surface; workpiece cores largely retain their toughness and ductility; and it produces case hardness depths of up to 0.25 inches (6.4 mm). In some cases it serves as a remedy for undesired decarburization that happened earlier in a manufacturing process.Celobar incident
The Celobar incident was a pharmaceutical fraud that occurred in Brazil in 2003, and resulted in the death of more than twenty X-ray patients by barium poisoning.Laboratório Enila was a small Brazilian pharmaceutics manufacturer who made an oral X-ray contrast medium trademarked Celobar. The medium's main ingredient was pharmaceutics-grade barium sulfate (BaSO4) imported from Germany. In 2003, without having the necessary expertise or authorization, they tried to manufacture BaSO4 in-house from much-cheaper technical-grade barium carbonate (BaCO3).
Non-reacted carbonate and other barium salts that remained in the adulterated product killed nine patients. The first death was Ricardo Diomedes, who had taken Celobar on May 21, 2003 at a clinic in Nova Iguaçu near Rio de Janeiro. A few hours later he was suffering from vomiting, diarrhea, abdominal pains, and weakness; he died the next day in Nilópolis. Postmortem exams confirmed that barium poisoning was the cause of death. Analysis of the Celobar by the Oswaldo Cruz Institute showed up to 14% unreacted carbonate (the maximum allowed limit being 0.001%). The other eight deaths occurred in the state of Goiás, where most of the contaminated lot had been shipped. (Coincidentally the same state as the Goiânia accident.)
Authorities were warned after the first deaths, recalled the lot, and closed the laboratory, which eventually went bankrupt.
On January 29, 2009, Enila's CEO (Márcio D'Icahahy Câmara Lima), and the chemist who carried out the synthesis (Antônio Carlos Fonseca da Silva) were sentenced to 20 and 22 years in jail, respectively.Friedrich Gabriel Sulzer
Friedrich Gabriel Sulzer (10 October 1749 – 14 December 1830) was a German physician from Gotha, Thuringia.Sulzer had a large collection of minerals and published also new results from new species. In 1791, Sulzer published together with Johann Friedrich Blumenbach their results on a new mineral he had acquired. He named the mineral strontianite (strontium carbonate) and made clear that it was distinct from the witherite (barium carbonate) and stated that it contained a new element.He was head of a veterinary school and a midwifery school and chief physician for the local spa in Ronneburg, Thuringia. Additionally, he was the physician for Dorothea von Medem and her sister Elisa von der Recke. He was part of the Musenhof der Herzogin von Kurland.
In 1774, Sulzer, a companion of Johann Wolfgang von Goethe, devoted a whole academic monography in the domain of social sciences and natural history to hamsters, entitled "An approach to a natural history of the hamster" ("Versuch einer Naturgeschichte des Hamsters"). In several instances, he used the hamster to document the equal rights of all beings, including Homo sapiens.Jasperware
Jasperware, or jasper ware, is a type of pottery first developed by Josiah Wedgwood in the 1770s. Usually described as stoneware, it has an unglazed matte "biscuit" finish and is produced in a number of different colours, of which the most common and best known is a pale blue that has become known as Wedgwood Blue. Relief decorations in contrasting colours (typically in white but also in other colours) are characteristic of jasperware, giving a cameo effect. The reliefs are produced in moulds and applied to the ware as sprigs.After several years of experiments, Wedgwood began to sell jasperware in the late 1770s, at first as small objects, but from the 1780s adding large vases. It was extremely popular, and after a few years many other potters devised their own versions. Wedgwood continued to make it into the 21st century. The decoration was initially in the fashionable Neoclassical style, which was often used in the following centuries, but it could be made to suit other styles. Wedgwood turned to leading artists outside the usual world of Staffordshire pottery for designs. High-quality portraits, mostly in profile, of leading personalities of the day were a popular type of object, matching the fashion for paper-cut silhouettes. The wares have been made into a great variety of decorative objects, but not typically as tableware or teaware. Three-dimensional figures are normally found only as part of a larger piece, and are typically in white. Teawares are usually glazed on the inside.
In the original formulation the mixture of clay and other ingredients is tinted throughout by adding dye (often described as "stained"); later the formed but unfired body was merely covered with a dyed slip, so that only the body near the surface had the colour. These types are known as "solid" and "dipped" (or "Jasper dip") respectively. The undyed body was white when fired, sometimes with a yellowish tinge; cobalt was added to elements that were to stay white.Rodenticide
Rodenticides, colloquially rat poison, are typically non-specific pest control chemicals made and sold for the purpose of killing rodents.
Some rodenticides are lethal after one exposure while others require more than one. Rodents are disinclined to gorge on an unknown food (perhaps reflecting an adaptation to their inability to vomit), preferring to sample, wait and observe whether it makes them or other rats sick. This phenomenon of poison shyness is the rationale for poisons that kill only after multiple doses.
Besides being directly toxic to the mammals that ingest them, including dogs, cats, and humans, many rodenticides present a secondary poisoning risk to animals that hunt or scavenge the dead corpses of rats.Strontium carbonate
Strontium carbonate (SrCO3) is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.Witherite
Witherite is a barium carbonate mineral, BaCO3, in the aragonite group. Witherite crystallizes in the orthorhombic system and virtually always is twinned. The mineral is colorless, milky-white, grey, pale-yellow, green, to pale-brown. The specific gravity is 4.3, which is high for a translucent mineral. It fluoresces light blue under both long- and short-wave UV light, and is phosphorescent under short-wave UV light.Witherite forms in low-temperature hydrothermal environments. It is commonly associated with fluorite, celestine, galena, barite, calcite, and aragonite. Witherite occurrences include: Cave-in-Rock, Illinois, US; Pigeon Roost Mine, Glenwood, Arkansas, US; Settlingstones Mine Northumberland; Alston Moor, Cumbria; Anglezarke, Lancashire and Burnhope, County Durham, England; Thunder Bay area, Ontario, Canada, Germany, and Poland (Tarnowskie Góry and Tajno at Suwałki Region).
Witherite was named after William Withering (1741–1799) an English physician and naturalist who in 1784 published his research on the new mineral. He could show that barite and the new mineral were two different minerals.
Vitamin K antagonists