Phosgenite

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Phosgenite
Phosgenite-34631.jpg
Crystal of phosgenite from the Monteponi Mine, Iglesias, Sardinia, Italy (size: 3.0 x 3.0 x 2.5 cm)
General
Category Carbonate minerals
Formula
(repeating unit)
(PbCl)2CO3
IMA symbol Pho [1]
Strunz classification 5.BE.20
Crystal system Tetragonal
Crystal class Ditetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space group P4/mbm
Unit cell a = 8.16 Å, c = 8.883(6) Å; Z = 4
Identification
ColorPale yellow to yellowish brown, pale brown, smoky brown, smoky violet, colorless, pale rose, gray, yellowish gray, pale green
Crystal habit Short prismatic crystals, granular, massive
Cleavage Distinct on {001} and {110}, indistinct on {100}
Fracture Conchoidal
Tenacity Sectile, flexible perpendicular to {001}
Mohs scale hardness2–3
Luster Adamantine
Streak White
Diaphaneity Transparent to translucent
Specific gravity 6.12 – 6.15
Optical propertiesUniaxial (+); anomalously biaxial if strained
Refractive index nω = 2.118 nε = 2.145
Birefringence δ = 0.027
Pleochroism Weakly pleochroic with O – reddish and E – greenish in thick sections.
Ultraviolet fluorescence Fluoresces yellow under LW and SW UV
Solubility Soluble in dilute nitric acid with effervescence, decomposes slowly in cold water
References [2] [3] [4] [5]

Phosgenite is a rare mineral consisting of lead carbonate chloride, (PbCl)2CO3. The tetragonal crystals are prismatic or tabular in habit: they are usually colorless and transparent, and have a brilliant adamantine lustre. Sometimes the crystals have a curious helical twist about the tetrad or principal axis. The hardness is 3 and the specific gravity 6.3. The mineral is rather sectile, and consequently was earlier known as corneous lead, (German Hornblei). [6]

Contents

Name and occurrence

An example of the mineral Phosgenite on display at the Royal Ontario Museum Phosgenite-RoyalOntarioMuseum-Jan18-09.jpg
An example of the mineral Phosgenite on display at the Royal Ontario Museum

The name phosgenite was given by August Breithaupt in 1820, after phosgene, carbon oxychloride, because the mineral contains the elements carbon, oxygen, and chlorine. [6]

It was found associated with anglesite and matlockite in cavities within altered galena in a lead mine at Cromford, near Matlock: hence its common name cromfordite. [7] Crystals are also found in galena at Monteponi near Iglesias in Sardinia, and near Dundas in Tasmania. [6] It has also been reported from Laurium, Greece; Tarnowitz, Poland; the Altai district, Siberia; the Touissit mine, near Oujda, Morocco; Sidi Amor ben Salem, Tunisia; Tsumeb, Namibia; Broken Hill, New South Wales; and Boleo, near Santa Rosalía, Baja California Sur. In the US it has been reported from the Terrible mine, Custer County, Colorado; the Stevenson-Bennett mine, Organ Mountains, Doña Ana County, New Mexico; and the Mammoth mine, Tiger, Pinal County, Arizona. [3]

Crystals of phosgenite, and also of the corresponding bromine compound PbBr2CO3, have been prepared artificially. [6]

See also

Related Research Articles

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Sphalerite is a sulfide mineral with the chemical formula (Zn,Fe)S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with galena, chalcopyrite, pyrite, calcite, dolomite, quartz, rhodochrosite, and fluorite.

<span class="mw-page-title-main">Galena</span> Natural mineral form of lead sulfide

Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver.

<span class="mw-page-title-main">Azurite</span> Copper carbonate mineral

Azurite is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum. Copper (Cu2+) gives it its blue color.

<span class="mw-page-title-main">Cerussite</span> Lead carbonate mineral

Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate (PbCO3), and is an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name céruse to the mineral, whilst the present form, cerussite, is due to W. Haidinger (1845). Miners' names in early use were lead-spar and white-lead-ore.

<span class="mw-page-title-main">Wulfenite</span> Molybdate mineral

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".

<span class="mw-page-title-main">Anglesite</span> Lead sulfate mineral

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<span class="mw-page-title-main">Murdochite</span>

Murdochite is a mineral combining lead and copper oxides with the chemical formula PbCu
6
O
8−x
(Cl,Br)
2x
 (x ≤ 0.5).

<span class="mw-page-title-main">Mimetite</span> Lead arsenate chloride mineral

Mimetite is a lead arsenate chloride mineral (Pb5(AsO4)3Cl) which forms as a secondary mineral in lead deposits, usually by the oxidation of galena and arsenopyrite. The name derives from the Greek Μιμητής mimetes, meaning "imitator" and refers to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite (Pb5(PO4)3Cl) and with vanadinite (Pb5(VO4)3Cl). Notable occurrences are Mapimi, Durango, Mexico and Tsumeb, Namibia.

<span class="mw-page-title-main">Alstonite</span>

Alstonite, also known as bromlite, is a low temperature hydrothermal mineral that is a rare double carbonate of calcium and barium with the formula BaCa(CO
3
)
2
, sometimes with some strontium. Barytocalcite and paralstonite have the same formula but different structures, so these three minerals are said to be trimorphous. Alstonite is triclinic but barytocalcite is monoclinic and paralstonite is trigonal. The species was named Bromlite by Thomas Thomson in 1837 after the Bromley-Hill mine, and alstonite by August Breithaupt of the Freiberg Mining Academy in 1841, after Alston, Cumbria, the base of operations of the mineral dealer from whom the first samples were obtained by Thomson in 1834. Both of these names have been in common use.

<span class="mw-page-title-main">Cotunnite</span>

Cotunnite is the natural mineral form of lead(II) chloride (PbCl2). Unlike the pure compound, which is white, cotunnite can be white, yellow, or green. The density of mineral samples spans range 5.3–5.8 g/cm3. The hardness on the Mohs scale is 1.5–2. The crystal structure is orthorhombic dipyramidal and the point group is 2/m 2/m 2/m. Each Pb has a coordination number of 9. Cotunnite occurs near volcanoes: Vesuvius, Italy; Tarapacá, Chile; and Tolbachik, Russia.

<span class="mw-page-title-main">Bournonite</span> Sulfosalt mineral species

Bournonite is a sulfosalt mineral species, trithioantimoniate of lead and copper with the formula PbCuSbS3.

<span class="mw-page-title-main">Leadhillite</span> Lead sulfate carbonate hydroxide mineral

Leadhillite is a lead sulfate carbonate hydroxide mineral, often associated with anglesite. It has the formula Pb4SO4(CO3)2(OH)2. Leadhillite crystallises in the monoclinic system, but develops pseudo-hexagonal forms due to crystal twinning. It forms transparent to translucent variably coloured crystals with an adamantine lustre. It is quite soft with a Mohs hardness of 2.5 and a relatively high specific gravity of 6.26 to 6.55.

<span class="mw-page-title-main">Crocoite</span> Lead chromate mineral

Crocoite is a mineral consisting of lead chromate, PbCrO4, and crystallizing in the monoclinic crystal system. It is identical in composition with the artificial product chrome yellow used as a paint pigment.

<span class="mw-page-title-main">Boleite</span>

Boleite is a complex halide mineral with formula: KPb26Ag9Cu24(OH)48Cl62. It was first described in 1891 as an oxychloride mineral. It is an isometric mineral which forms in deep-blue cubes. There are numerous minerals related to boleite, such as pseudoboleite, cumengite, and diaboleite, and these all have the same complex crystal structure. They all contain bright-blue cubic forms and are formed in altered zones of lead and copper deposits, produced during the reaction of chloride bearing solutions with primary sulfide minerals.

<span class="mw-page-title-main">Matlockite</span>

Matlockite is a rare lead halide mineral, named after the town of Matlock in Derbyshire, England, where it was first discovered in a nearby mine. Matlockite gives its name to the matlockite group which consists of rare minerals of a similar structure.

Guettardite is a rare arsenic-antimony lead sulfosalt mineral with the chemical formula Pb(Sb,As)2S4. It forms gray black metallic prismatic to acicular crystals with monoclinic symmetry. It is a dimorph of the triclinic twinnite.

<span class="mw-page-title-main">Laurionite</span>

Laurionite is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group.

<span class="mw-page-title-main">Paralaurionite</span>

Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite group. The name is derived from para-, the Greek for "near", and laurionite, because of its polymorphic relationship to it. Bright, yellow tips of thorikosite can form on paralaurionite crystals and paralaurionite may also be intergrown with mendipite.

<span class="mw-page-title-main">Carminite</span> Anhydrous arsenate mineral containing hydroxyl

Carminite (PbFe3+2(AsO4)2(OH)2) is an anhydrous arsenate mineral containing hydroxyl. It is a rare secondary mineral that is structurally related to palermoite (Li2SrAl4(PO4)4(OH)4). Sewardite (CaFe3+2(AsO4)2(OH)2) is an analogue of carminite, with calcium in sewardite in place of the lead in carminite. Mawbyite is a dimorph (same formula, different structure) of carminite; mawbyite is monoclinic and carminite is orthorhombic. It has a molar mass of 639.87 g. It was discovered in 1850 and named for the characteristic carmine colour.

<span class="mw-page-title-main">Mammothite</span>

Mammothite is a mineral found in the Mammoth mine in Tiger, Arizona and also in Laurium, Attika, Greece. This mineral was named in 1985 by Donald R. Peacor, Pete J. Dunn, G. Schnorrer-Köhler, and Richard A. Bideaux, for the Mammoth vein (one of the two main veins in the mine) and the town of Mammoth, Arizona, which was named for the mine. The mammothite that is found in Arizona exist as euhedral crystals imbedded in micro granular, white colored anglesite with a saccharoidal texture. The associated minerals include phosgenite, wulfenite, leadhillite and caledonite. In Greece, the mammothite exists as small euhedral crystals and also as microscopic rock cavities lined with projecting crystals within the slags. The associated minerals here are cerussite, phosgenite and matlockite. The ideal chemical formula for mammothite is Pb6Cu4AlSb5+O2(OH)16Cl4(SO4)2.

References

  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. Mineralienatlas
  3. 1 2 Handbook of Mineralogy
  4. Mindat.org
  5. Webmineral data
  6. 1 2 3 4 Wikisource-logo.svg One or more of the preceding sentences incorporates text from a publication now in the public domain : Spencer, Leonard James (1911). "Phosgenite". In Chisholm, Hugh (ed.). Encyclopædia Britannica . Vol. 21 (11th ed.). Cambridge University Press. p. 474.
  7. "Phosgenite and Matlockite in Derbyshire (Part 1). T. Bridges, M. E. Smith. Journal of the Russell Society Volume 1, No. 2, p.7–14, 1983 Retrieved on 2011-01-11