The thiospinel group is a group of
sulfide minerals with a general formula where A is nominally a +2 metal, B is a +3 metal and X is -2 sulfide or similar anion (selenide or telluride). ''Thio'' refers to sulfur and ''spinel'' indicates their
isometric spinel-like structure.
[Thiospinel group on Mindat]
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As the chalcogen
The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioac ...
s S, Se and Te are less electronegative
Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the d ...
than oxygen, the bonding in these materials is generally more covalent
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms ...
than in the oxospinels. Some are ( magnetic) semiconductor
A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...
s but others display, at times complicated, metallic
Metallic may be a reference to:
*Metal
* Metalloid, metal-like substance
*Metallic bonding, type of chemical bonding
* Metallicity, in astronomy the proportion of elements other than helium and hydrogen in an object
*Metallic color, a color that ...
behavior, often coupled with equally complicated magnetic properties. The assignment of oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
s is also not always as straightforward as in the more ionic oxocompounds, as is shown in the case of carrollite
Carrollite, CuCo2S4, is a sulfide of copper and cobalt, often with substantial substitution of nickel for the metal ions, and a member of the linnaeite group. It is named after the type locality in Carroll County, Maryland, US, at the Patapsco m ...
.
Group members include:
* Cadmoindite –
* Carrollite
Carrollite, CuCo2S4, is a sulfide of copper and cobalt, often with substantial substitution of nickel for the metal ions, and a member of the linnaeite group. It is named after the type locality in Carroll County, Maryland, US, at the Patapsco m ...
–
* Fletcherite –
* Greigite
Greigite is an iron sulfide mineral with the chemical formula . It is the sulfur equivalent of the iron oxide magnetite (Fe3O4). It was first described in 1964 for an occurrence in San Bernardino County, California, and named after the mineralogis ...
–
* Indite
Indite is an extremely rare indium-iron sulfide mineral, found in Siberia. Its chemical formula is FeIn2S4.
It occurs as replacement of cassiterite in hydrothermal deposits. It is associated with dzhalindite, cassiterite and quartz. It was firs ...
–
* Kalininite Kalininite ( Zn Cr2 S4) is a thiospinel mineral found in Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its interna ...
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* Linnaeite
Linnaeite is a cobalt sulfide mineral with the composition Co+2Co+32S4. It was discovered in 1845 in Västmanland, Sweden, and was named to honor Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobi ...
–
* Polydymite
Polydymite, Ni2+Ni23+S4, is a supergene thiospinel sulfide mineral associated with the weathering of primary pentlandite nickel sulfide.
Polydymite crystallises in the isometric system, with a hardness of 4.5 to 5.5 and a specific gravity of ab ...
-
* Siegenite
Siegenite (also called grimmite, or nickel cobalt sulfide) is a ternary transition metal dichalcogenide compound with the chemical formula (Ni,Co)3S4. It has been actively studied as a promising material system for electrodes in electrochemical en ...
–
* Tyrrellite –
* Violarite
Violarite ( Fe2+ Ni23+ S4) is a supergene sulfide mineral associated with the weathering and oxidation of primary pentlandite nickel sulfide ore minerals.
Violarite crystallises in the isometric system, with a hardness of 4.5 to 5.5 and a speci ...
–
References
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