Bismoclite is a

bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

oxohalide In chemistry, oxohalides or oxyhalides are a group of chemical compounds with the chemical formula , where X is a halogen, and A is an element different than O and X. Known oxohalides have fluorine (F), chlorine (Cl), bromine (Br), and/or iodine ( ...

mineral with formula BiOCl. It is the naturally occurring form of

bismuth oxychloride Bismuth oxychloride is an inorganic compound of bismuth with the formula Bi O Cl. It is a lustrous white solid used since antiquity, notably in ancient Egypt. Light wave interference from its plate-like structure gives a pearly iridescent light r ...

. The name was derived from its chemical constituents. It is a secondary bismuth mineral first thought to be composed of bismuthyl ions (BiO⁺) and chloride anions, however, the existence of the diatomic bismuthyl ion is doubtful. It is a member of the matlockite group. It was first described in 1935 from alluvium near bismuth-bearing pegmatites in South Africa. It has been found in association with

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic c ...

and in

greisen Greisen is a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas (mostly muscovite). Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic-hy ...

. Associated minerals include

bismutite Bismutite or bismuthite is a bismuth carbonate mineral with formula Bi2(CO3)O2 ( bismuth subcarbonate). Bismutite occurs as an oxidation product of other bismuth minerals such as bismuthinite and native bismuth in hydrothermal veins and pegma ...

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...

jarosite Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct dur ...

alunite Alunite is a hydroxylated aluminium potassium sulfate mineral, formula potassium, Kaluminium, Al3(sulfur, Soxygen, O4)2(Ohydrogen, H)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum ...

cerussite Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate with the chemical formula PbCO3, and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was ...

atacamite Atacamite is a copper halide mineral: a copper(II) chloride hydroxide with formula Cu2Cl(OH)3. It was first described for deposits in the Atacama Desert of Chile in 1802 by Dmitri de Gallitzin. The Atacama Desert is also the namesake of the min ...

connellite Connellite is a rare mineral species, a hydrous copper chloro-sulfate, Cu19(OH)32(SO4)Cl4·3H2O, crystallizing in the hexagonal system. It occurs as tufts of very delicate acicular crystals of a fine blue color, and is associated with other copper ...

. Occurrences include the type locality at Jackals Water, SW of

Prieska Prieska is a town on the south bank of the Orange River, in the province of the Northern Cape, in western South Africa. It is located on the southern bank of the Orange River, 130 km north-west of Britstown and 75 km south-east of Maryd ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

; Bygoo, Australia; the Tintic district in the

East Tintic Mountains The East Tintic Mountains are a mountain range in central Juab, Utah, and Tooele counties in Utah, United States on the east margin of the Great Basin just west of the Wasatch Front about south-southeast of Salt Lake City. The community of Eur ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

; and from

Dalbeattie Dalbeattie (, , meaning 'haugh of the birch', or 'drowned haugh' (i.e. liable to flood) is a town in the historical county of Kirkcudbrightshire in Dumfries and Galloway, Scotland. Dalbeattie is in a wooded valley on the Urr Water east of Ca ...

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

Crystal structure

The crystal structure of bismoclite was found to be composed of linked decahedrons, specifically a

square antiprism In geometry, the square antiprism is the second in an infinite family of antiprisms formed by an even number, even-numbered sequence of triangle sides closed by two polygon caps. It is also known as an ''anticube''. If all its faces are regular ...

. These decahedrons consist of 2 squares with sides of 3.487 Å (O-O-O-O and Cl-Cl-Cl-Cl) connected by 8

isosceles triangle In geometry, an isosceles triangle () is a triangle that has two Edge (geometry), sides of equal length and two angles of equal measure. Sometimes it is specified as having ''exactly'' two sides of equal length, and sometimes as having ''at le ...

s (O-Cl-O and Cl-O-Cl), with a bismuth atom at the centre. The Bi-O distances and Bi-Cl distances are 2.316 Å and 3.059 Å, respectively. The O-Cl distances in the triangles are 3.249 Å. The decahedrons are linked to each other through shared O-Cl sides.

Practical significance

Bismoclite is a rare secondary mineral, a product of the oxidation of basic bismuth ores in the presence of active

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

ions. In addition, bismoclite does not represent the final oxidation product. For example, during the oxidation of native bismuth under hypergenesis conditions, the intermediate product is bismuth chloride, and the final product is a sparingly soluble carbonate.'' Rundqvist D. V., Tatarinov P. M.'' Minerals and parageneses of minerals from endogenous deposits. — Leningrad: Science, Leningrad branch, 1975. — 131 p. For this reason, bismoclite is found in deposits of

bismuthinite Bismuthinite is a mineral consisting of bismuth sulfide ( Bi2 S3). It is an important ore for bismuth. The crystals are steel-grey to off-white with a metallic luster. It is soft enough to be scratched with a fingernail and rather dense. Bism ...

and

native bismuth Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

in much smaller volumes than the similar minerals

bismite Bismite is a bismuth oxide mineral, bismuth trioxide or Bi2O3. It is a monoclinic mineral, but the typical form of occurrence is massive and clay-like with no macroscopic crystals. The color varies from green to yellow. It has a Mohs hardness of ...

and

, in which it is often present as an impurity. With the same success as these latter, it can be used to obtain bismuth and its compounds. However, the main significance of bismoclite is purely scientific, allowing more accurate monitoring and determination of geochemical processes in zones of oxidation and weathering of the main bismuth ores. * In medical diagnostics, bismoclite (in the form of purified

) is used as a local radiocontrast agent. * In addition, in the production of cosmetics, bismoclite is used as an enhancing agent; it gives a pearlescent shine to

lipstick Lipstick is a cosmetics, cosmetic product used to apply coloration and texture to lips, often made of wax and oil. Different pigments are used to produce color, and minerals such as silica may be used to provide texture. The use of lipstick ...

, nail polish and

eye shadow Eye shadow (or eyeshadow) is a cosmetic applied primarily to the eyelids to attract attention to the wearer's eyes, making them stand out or look more attractive. Eye shadow can also be applied under the eyes, on the cheeks, or to brow bones. ...

. * In the chemical industry, in the process of

cracking Cracking may refer to: * Cracking, the formation of a fracture or partial fracture in a solid material studied as fracture mechanics ** Performing a sternotomy * Fluid catalytic cracking, a catalytic process widely used in oil refineries for crac ...

hydrocarbons, bismuth oxochloride is used as a

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

References

Bismuth minerals Oxide minerals Halide minerals Tetragonal minerals Minerals in space group 129 {{halide-mineral-stub