Paramontroseite | |
---|---|
General | |
Category | Oxide minerals |
Formula (repeating unit) | VO2 |
IMA symbol | Pmto [1] |
Strunz classification | 4.DB.15a |
Dana classification | 4.4.11.1 |
Crystal system | Orthorhombic |
Space group | Pbnm (no. 62) |
Unit cell | a=4.905 b=9.422 c=2.916 |
Identification | |
Color | Black to grayish black |
Luster | Submetallic |
Streak | Black |
Paramontroseite (V4+O2) is a relatively rare orthorhombic vanadium oxide mineral in the Ramsdellite Group. Synthetic paramontroseite may have applications in medicine, batteries and electronics.
The name paramontroseite is derived from the Greek παρα (para), meaning near, and montroseite, a related mineral. [2] The name was chosen due to the mineral's paramorphic relationship to the host mineral montroseite. [3] Montroseite is named after Montrose County, Colorado, USA, where it was first found. [4] [lower-alpha 1] Names in other languages include Paramontroseit (German), paramontroseita (Spanish), парамонтрозеит (Russian) and 副黑钒矿 副黑铁钒矿 (Chinese). [7] Synonyms are Inorganic Crystal Structure Database (ICSD) 22303 and Powder Diffraction File (PDF) 25-1003. [2]
Paramontroseite is associated with montroseite and corvusite. It is found in relatively unoxidized Colorado Plateau-type uranium–vanadium ores in sandstones. [8] The type locality is Bitter Creek Mine, Paradox Valley, Uravan District, Montrose County, Colorado, USA. [9] In the USA it is found in Montrose County, Colorado, San Miguel County, Colorado, Mesa County, Colorado, Emery County, Utah, Apache County, Arizona, McKinley County, New Mexico and Fall River County, South Dakota. [10] It has also been reported from locations in the Czech Republic, Mendoza Province, Argentina and the Mounana uranium mine near Franceville, Gabon. [10]
Paramontrosite has also been found in an outcrop on the Van Irvine Ranch in the Pumpkin Buttes area of Wyoming, USA, associated with sulfides in red sandstone. [11] It is found in a zone where the sandstone changes color from red to gray. The black paramontroseite cements grains of sand into nodular masses that enclose smaller pyrite masses. [12] The irregular concretionary masses are up to 1 foot (0.30 m) across. [13] Vanadium salts have given a greenish coating to the exposed surfaces of these masses. The masses are anomalously radioactive and the surrounding sandstone is weakly radioactive. The radioactivity is mostly caused by tiny specks of coffinite in the paramontroseite. [12] When a section is polished the paramontroseite completely fills the gaps between the grains of sand. It is very soft and has a gray color that is slightly lighter than quartz gray. There is strong anisotrophism and many bright multi-colored internal reflections. [13]
Deposits of montroseite (V,Fe)OOH and paramontroseite VO2 have been found in the Saltwash Sandstone Member of the Upper Jurassic Morrison Formation in the Colorado Plateau. From the diffraction characteristics of the paramontroseite there seem to be two distinct generations: a primary paramontroseite with good crystalline structure and a product of montroseite oxidation with poor crystalline structure. [14] The paramontroseite found in this region is among the neutral minerals in the mid-range of vanadium valence (+4) above the primary ore of montroseite (+3) but below minerals such as carnotite (+5) and pascoite (+5). [15]
Paramontroseite is a metastable form of vanadium dioxide (VO2) that results from oxidation of montroseite. [16] It is formed by dehydrogenation of montroseite. [8] Paramontroseite seems to be the most common initial product of oxidation of montroseite. [17] The primary difference between the crystal structures of the two minerals is that the oxygen–oxygen distance increases from 2.63Å in montroseite to 3.87Å in paramontroseite due to the loss of hydrogen in the latter. [16] The vanadium–oxygen distances are also somewhat shorter in paramontroseite than in montroseite, as would be expected when the vanadium is oxidized from +3 to +4 when the hydrogen is removed. [18]
The montroseite, VO(OH), is deposited in crystalline masses in a sandstone matrix by some unknown process. Usually iron occurs in place of some of the vanadium. Oxygen in the air or groundwater then oxidizes the crystallised montroseite at temperatures under 50 °C through the reaction:
During the solid state alteration process the hydrogen atoms migrate through the crystal structure to the surface, where they combine with oxygen. In the process there is a slight shift in the crystal structure, but the structure remains intact. [19] The vanadium-oxygen bonds have not been broken and the hexagonal close-packed oxygen framework has not been disrupted. [20] In some cases there may be an intermediate "diffuse A" phase. [19] The process by which montroseite is altered to paramontroseite seems analogous to the magnetite → maghemite, lepidocrocite → maghemite, and goethite → hematite processes. [21]
Paramontroseite is not stable and is destroyed by weathering, replaced by minerals of the corvusite type. [19] The paramontroseite reacts under neutral or acid conditions to form many compounds such as vanadyl vanadate and metal vanadates such as hewettite, hummerite, pascoite and rossite. [22] Paramontroseite may dissolve in slightly alkaline conditions, then combine with Ca++ to form simplotite: [23]
Autophagy is a process of cellular degradation that is essential in preserving homeostasis of cells. It is often thought that when autophagosomes encapsulate and trap inorganic nanoparticles they may be unable to degrade them and the cell's well-being may be threatened. However, experiments have shown that nanocrystals of paramontroseite induce cyto-protective autophagy in cultured HeLa cells. It is possible that this may have value in therapies. [24]
Montroseite and paramontroseite microspheres have been synthesized by hydrothermal carbonization of sucrose and calcinated to form V2O3-VO2-C core-shell microspheres. These have been used experimentally as cathode materials for a lithium-ion battery. [25] Y. Xu and colleagues of the University of Science and Technology of China have shown that synthetic montroseite VOOH hollow structures can convert topochemically to paramontroseite without altering the size and appearance of the structures. Both forms appear to have potential in lithium-ion batteries as anode materials. [26]
Monoclinic vanadium dioxide VO2(M) is potentially of great value for applications such as intelligent temperature sensors and smart windows. The classic solid state transformation from vanadium precursors to rutile VO2(R) is slow and costly. A transformation from goethite VOOH to synthetic "paramontroseite" VO2 to the desired monoclinic VO2(M) promises to greatly reduce cost and time. [27]
Paramontroseite was first described before 1959. It is a member of the Ramsdellite Group. [28] It is classified as follows: [29]
Physical properties of Paramontroseite include
Empirical formula | V4+O2 [2] |
Chemical formula | VO2 [2] |
Molecular mass | 82.94 gm (61.42% vanadium and 38.58% oxygen by weight). [2] |
Hardness | soft [30] |
Fracture | brittle [31] |
Cleavage | good [31] |
Density (g/cm3) | 4 (measured), 4.095 (calculated) [32] |
Calculated electron density | 3.85 gm/cc [33] |
Calculated fermion index | 0.0017206735 [33] |
Calculated boson index | 0.9982793265 [33] |
Radioactive | no [33] [lower-alpha 2] |
The X-ray powder diffraction pattern for a Bitter Creek mine sample is 3.39 (100), 2.645 (50), 4.35 (35), 2.213 (35), 1.426 (35), 2.479 (25), 2.179 (25). In this sample the chemistry was: [35]
V2O4 | 72.5 |
V2O3 | 10.5 |
FeO | 8.8 |
H2O | 5.0 |
A sample from Matchless mine, Colorado, USA had chemistry: [36]
V2O4 | 66.9 |
SiO2 | 6.12 |
Al2O3 | 3.00 |
V2O3 | 11.10 |
FeO | 8.26 |
H2O | 4.82 |
The measured chemistry of a microprobe fragment in the gray phase by the RRUFF project gave metals in the ratio: V4+ (82%), Fe3+ (9%), U6+ (4%) and Al (2%), with one metal atom per two oxygen atoms. The lightest phase was uranophane. [34]
Paramontroseite is opaque and black to grayish black in color. [37] [lower-alpha 3] Its optical class is biaxial. [37] It has a sub-metallic luster and a black streak. From the Gladstone–Dale relation (KC = 0.393), the NCalc is 2.61 where Ncalc=Dcalc*KC+1, or 2.57 where Ncalc=Dmeas*KC+1. [39]
Paramontroseite crystal properties include:
Crystal structure | orthorhombic - dipyramidal [40] |
Cell dimensions | a = 4.905Å, b = 9.422Å, c = 2.916Å, Z = 4; V = 134.76 Den (Calc) = 4.09. [40] |
Ratio:a:b:c | 0.5205:1:0.3094. [40] |
Point group | 2/m 2/m 2/m. [41] |
Space group | Pbnm [42] |
Space group number | 62. [42] |
X-Ray diffraction by intensity (I/Io) | 3.39(1), 2.649(0.5), 4.35(0.35). [40] |
Pyrochlore2Nb2O6(OH,F) is a mineral group of the niobium end member of the pyrochlore supergroup. Pyrochlore is also a term for the crystal structure Fd3m. The name is from the Greek πῦρ, fire, and χλωρός, green because it typically turns green on ignition in classic blowpipe analysis.
Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb5(VO4)3Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals. It is an uncommon mineral, formed by the oxidation of lead ore deposits such as galena. First discovered in 1801 in Mexico, vanadinite deposits have since been unearthed in South America, Europe, Africa, and North America.
Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula K2(UO2)2(VO4)2·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.
Creedite is a calcium aluminium sulfate fluoro hydroxide mineral with formula: Ca3Al2SO4(F,OH)10·2(H2O). Creedite forms colorless to white to purple monoclinic prismatic crystals. It often occurs as acicular radiating sprays of fine prisms. It is translucent to transparent with indices of refraction of nα = 1.461 nβ = 1.478 nγ = 1.485. It has a Mohs hardness of 3.5 to 4 and a specific gravity of 2.7.
Murdochite is a mineral combining lead and copper oxides with the chemical formula PbCu
6O
8−x(Cl,Br)
2x (x ≤ 0.5).
Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO2) and is important as an ore of manganese. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8. Its name is from the Greek for fire and to wash, in reference to its use as a way to remove tints from glass.
Vivianite (Fe2+
3(PO
4)
2·8H
2O) is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg2+, and calcium Ca2+ may substitute for iron Fe2+ in the structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals. Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone. Vivianite can also appear on the iron coffins or on the corpses of humans as a result of a chemical reaction of the decomposing body with the iron enclosure.
Torbernite, also known as chalcolite, is a relatively common mineral with the chemical formula Cu[(UO2)(PO4)]2(H2O)12. It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a secondary mineral. The chemical formula of torbernite is similar to that of autunite in which a Cu2+ cation replaces a Ca2+ cation. Torbernite tends to dehydrate to metatorbernite with the sum formula Cu[(UO2)(PO4)]2(H2O)8.
Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite.
Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte crystallizes in the hexagonal system. It forms as brown rounded to concretionary masses. Feroxyhyte is opaque, magnetic, has a yellow streak, and has a relative density of 4.2.
Linarite is a somewhat rare, crystalline mineral that is known among mineral collectors for its unusually intense, pure blue color. It is formed by the oxidation of galena and chalcopyrite and other copper sulfides. It is a combined copper lead sulfate hydroxide with formula PbCuSO4(OH)2. Linarite occurs as monoclinic prismatic to tabular crystals and irregular masses. It is easily confused with azurite, but does not react with dilute hydrochloric acid as azurite does. It has a Mohs hardness of 2.5 and a specific gravity of 5.3 – 5.5.
Empressite or tellursilberblende is a mineral form of silver telluride, AgTe. It is a rare, grey, orthorhombic mineral with which can form compact masses, rarely as bipyramidal crystals.
Ulvöspinel or ulvite is an iron titanium oxide mineral with formula: Fe2TiO4 or TiFe2+2O4. It forms brown to black metallic isometric crystals with a Mohs hardness of 5.5 to 6. It belongs to the spinel group of minerals, as does magnetite, Fe3O4.
In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.
A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, molybdenum, nickel, niobium, rhenium, selenium, tantalum, tellurium, tin, titanium, tungsten, vanadium, and zinc, as well as the gold group and the platinum group. Among the alloys found in native state have been brass, bronze, pewter, German silver, osmiridium, electrum, white gold, silver-mercury amalgam, and gold-mercury amalgam.
Pabstite is a barium tin titanium silicate mineral that is found in contact metamorphosed limestone. It belongs to the benitoite group of minerals. The chemical formula of pabstite is Ba(Sn,Ti)Si3O9. It is found in Santa Cruz, California. The crystal system of the mineral is hexagonal.
Plancheite is a hydrated copper silicate mineral with the formula Cu8Si8O22(OH)4•(H2O). It is closely related to shattuckite in structure and appearance, and the two minerals are often confused.
Magnesiopascoite is a bright orange mineral with formula Ca2Mg(V10O28)·16H2O. It was discovered in the U.S. state of Utah and formally described in 2008. The mineral's name derives from its status as the magnesium analogue of pascoite.
Rakovanite, (NH4)3Na3(V10O28) · 12H2O; formerly given as Na3(H3V10O28).15H2O; later, the ammonium ion was shown to be present and essential, is a member of the pascoite family. It is a transparent, brittle mineral occurring in the monoclinic crystal system. It is orange in color and has an orange-yellow colored streak. Rakovanite is soft with a Mohs hardness of 1 and a calculated density of 2.407g cm−3. It does not fluoresce in long- or short-wave ultraviolet radiation. Rakovanite crystals are up to one mm in maximum dimension and vary in habit from blocky to prismatic on [001], commonly exhibiting steps and striations parallel to [001]. Its name honors John Rakovan, former professor, Department of Geology and Environmental Earth Science, Miami University, State Mineralogist and Senior Museum Curator, New Mexico Bureau of Geology and Mineral Resources.