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Hexamolybdenum

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Hexamolybdenum
General
CategoryNative mineral alloy
Formula
(repeating unit)
(Mo,Ru,Fe,Ir,Os)
IMA symbolHmo[1]
Strunz classification1.XX.00
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m)
Space groupP63/mmc
Unit cella = 2.7506, c = 4.4318 [Å]
V = 29.04 Å3, Z = 2
Identification
Crystal habitInclusions and microscopic crystals
Specific gravity11.90 (calculated)
References[2][3][4]

Hexamolybdenum is a molybdenum dominant alloy discovered during a nanomineralogy investigation of the Allende meteorite.[4] Hexamolybdenum was discovered in a small ultrarefractory inclusion within the Allende meteorite.[4] This inclusion has been named ACM-1.[4] Hexamolybdenum is hexagonal, with a calculated density of 11.90 g/cm3.[4] The new mineral was found along with allendeite.[4] These minerals, are believed to demonstrate conditions during the early stages of the Solar System, as is the case with many CV3 carbonaceous chondrites such as the Allende meteorite.[4] Hexamolybdenum lies on a continuum of high-temperature alloys that are found in meteorites and allows a link between osmium, ruthenium, and iron rich meteoritic alloys.[4] The name hexamolybdenum refers to the crystal symmetry (primitive hexagonal) and the molybdenum rich composition.[4] The Allende meteorite fell in 1969 near Pueblito de Allende, Chihuahua, Mexico.[4]

Occurrence

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Hexamolybdenum was found as nano-crystals in an ultrarefractory inclusion in the Allende meteorite.[4] The Allende meteorite has shown to be full of new minerals, after nearly forty years it has produced one in ten of the now known minerals in meteorites.[4] This CV3 carbonaceous chondrite was the largest ever recovered on earth and is referred to as the best-studied meteorite in history.[4] The inclusion has only been viewed via electron microscopy.[4] The hexamolybdenum specimen was lost during an attempted ion probe analysis of a bordering grain.[4] Other specimens can be found, however, in the Smithsonian Institution's National Museum of Natural History Allende section USNM 3509HC12 and in section USNM 7590 of NWA 1934, another VC3 chondrite.[4]

It has also been reported from the NWA 1934 CV3 carbonaceous chondrite meteorite from the Erfoud region of Morocco and in the Danubian placer of Straubing, Bavaria.[2]

Chemical composition

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Hexamolybdenum is an (molybdenum, ruthenium, iron, iridium, osmium) alloy.[4]

Appearance

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Color, streak, luster, hardness, tenacity, cleavage, fracture, density, and refractive index could not be observed because the grain size was too small and the section bearing the mineral was optically thick.[4]

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Mindat.org
  3. ^ Webmineral data
  4. ^ a b c d e f g h i j k l m n o p q r Beckett, John R.; Rossman, George R. (2014). "Allendeite (Sc3Zr4O12 and hexamolybdenum (Mo, Ru, Fe), two new minerals from an ultrarefractory inclusion from the Allende meteorite". American Mineralogist. 99 (4): 654–666. Bibcode:2014AmMin..99..654M. doi:10.2138/am.2014.4667. S2CID 94914236.