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Barium sulfide is the
inorganic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during a ...
with the formula
Ba
Ba
S
S
. This colorless salt is an important precursor to other barium compounds including BaCO3 and the pigment lithopone, ZnS/BaSO4. Like other
chalcogenide: 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen The chalcogens () are the chemical elements in group (periodic table), group 16 of ...
s of the alkaline earth metals, BaS is a short
wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase (waves), phase on the wave, such as two adja ...

wavelength
emitter for
electronic display An electronic visual display, informally a screen, is a display device s, LED display and Vacuum fluorescent display, VF display, top to bottom. A display device is an output device for presentation of information in visual or Touch, tactile form ...
s. It is colorless, although like many sulfides, it is commonly obtained in impure colored forms.


Discovery, production and properties

BaS was prepared by the Italian alchemist Vincentius (or Vincentinus) Casciarolus (or Casciorolus, 1571-1624) via the thermo-chemical reduction of
BaSO4
BaSO<sub>4</sub>
(available as the mineral
barite Baryte, barite or barytes (, ) is a consisting of (4). Baryte is generally white or less, and is the main source of the element . The ''baryte group'' consists of baryte, (strontium sulfate), (lead sulfate), and (calcium sulfate). Baryte and c ...

barite
). It is currently manufactured by an improved version of Casciarolus's process using coke in place of flour and
charcoal or soil, and firing it (circa 1890) Charcoal is a lightweight black carbon Carbon (from la, carbo "coal") is a chemical element with the Symbol (chemistry), symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent ...

charcoal
. This kind of conversion is called a
carbothermic reactionCarbothermic reactions involve the reduction of substances, often metal oxides (O^2-), using carbon Carbon (from la, carbo "coal") is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic tab ...
: :BaSO4 + 2 C → BaS + 2 CO2 and also: :BaSO4 + 4 C → BaS + 4 CO The basic method remains in use today. BaS dissolves in water. These aqueous solutions, when treated with
sodium carbonate Sodium carbonate, ·10, (also known as Natrium Carbonate, washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield modera ...

sodium carbonate
or
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

carbon dioxide
, give a white solid of
barium carbonate Barium carbonate is the inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. However, the distinction is not clearly defin ...

barium carbonate
, a source material for many commercial barium compounds. According to Harvey (1957), Harvey E. Newton (1957). A History of Luminescence: From the Earliest Times until 1900. Memoirs of the American Physical Society, Philadelphia, J. H. FURST Company, Baltimore, Maryland (USA), Vol. 44, Chapter 1, pp. 11-43. in 1603, Vincenzo Cascariolo used
barite Baryte, barite or barytes (, ) is a consisting of (4). Baryte is generally white or less, and is the main source of the element . The ''baryte group'' consists of baryte, (strontium sulfate), (lead sulfate), and (calcium sulfate). Baryte and c ...

barite
, found at the bottom of Mount Paterno near
Bologna Bologna (, , ; egl, label=Bolognese dialect, Bolognese, Bulåggna ; lat, Bonōnia) is the capital and largest city of the Emilia-Romagna region in Northern Italy. It is the seventh most populous city in Italy with about 390,000 inhabitants ...

Bologna
, in one of his non-fruitful attempts to produce
gold Gold is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numb ...

gold
. After grinding and heating the mineral with charcoal under reducing conditions, he obtained a persistent
luminescent Luminescence is spontaneous emission of light Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be visual perception, perceived by the human eye. Visible light is usually defined ...

luminescent
material rapidly called ''Lapis Boloniensis'', or Bolognian stone. The
phosphorescence Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike flu ...

phosphorescence
of the material obtained by Casciarolo made it a curiosity. BaS crystallizes with the NaCl structure, featuring octahedral Ba2+ and S2− centres. The observed
melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can b ...

melting point
of barium sulfide is highly sensitive to impurities.


Safety

BaS is quite poisonous, as are related sulfides, such as CaS, which evolve toxic
hydrogen sulfide Hydrogen sulfide is a chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by havi ...

hydrogen sulfide
upon contact with water.


References

{{Sulfides Barium compounds Sulfides Cubic minerals Phosphors and scintillators