Phosgenite is a rare

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

consisting of

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

chlorocarbonate, (PbCl)₂CO₃. The

tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square ...

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

s are

prismatic An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are ''not'' prisms. The most familiar type of optical ...

or tabular in habit: they are usually colorless and transparent, and have a brilliant adamantine

lustre Lustre or Luster may refer to: Places * Luster, Norway, a municipality in Vestlandet, Norway ** Luster (village), a village in the municipality of Luster * Lustre, Montana, an unincorporated community in the United States Entertainment * '' ...

. Sometimes the crystals have a curious

helical Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

twist about the tetrad or principal axis. The

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

is 3 and the

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

6.3. The mineral is rather

sectile Sectility is the ability of a mineral to be cut into thin pieces with a knife. Minerals that are not sectile will be broken into rougher pieces when cut. Metals and paper are sectile. Sectility can be used to distinguish minerals of similar appea ...

, and consequently was earlier known as corneous lead, (German ''Hornblei'').

Name and occurrence

The name phosgenite was given by

August Breithaupt Johann Friedrich August Breithaupt (May 16, 1791 – September 22, 1873) was a German mineralogist and professor at Freiberg Mining Academy in Freiberg, Saxony. Biography He was born in Probstzella. He received his doctorate at the Universities ...

in 1820, from

phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, espe ...

, carbon oxychloride, because the mineral contains the elements

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

and

chlorine Chlorine is a chemical element with the 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 betwee ...

. It was found associated with

anglesite Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and ...

and

matlockite 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 (chemical formula: PbFCl) gives its name to the matlockite group which consists of rare ...

in cavities within altered

galena 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. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

in a lead mine at

Cromford Cromford is a village and civil parish in Derbyshire, England, in the valley of the River Derwent between Wirksworth and Matlock. It is north of Derby, south of Matlock and south of Matlock Bath. It is first mentioned in the 11th-century Do ...

, near Matlock: hence its common name cromfordite."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 Crystals are also found in galena at Monteponi near Iglesias in

Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...

, and near

Dundas Dundas may refer to: Places Australia * Dundas, New South Wales * Dundas, Queensland, a locality in the Somerset Region * Dundas, Tasmania * Dundas, Western Australia * Fort Dundas, a settlement in the Northern Territory 1824–1828 * Shire of ...

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. It has also been reported from

Laurium Laurium or Lavrio ( ell, Λαύριο; grc, Λαύρειον (later ); before early 11th century BC: Θορικός ''Thorikos''; from Middle Ages until 1908: Εργαστήρια ''Ergastiria'') is a town in southeastern part of Attica, Greec ...

, Greece; Tarnowitz, Poland; the Altai district,

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

; the Touissit mine, near

Oujda Oujda ( ar, وجدة; ber, ⵡⵓⵊⴷⴰ, Wujda) is a major Moroccan city in its northeast near the border with Algeria. Oujda is the capital city of the Oriental region of northeastern Morocco and has a population of about 558,000 people. It ...

, Morocco; Sidi Amor ben Salem, Tunisia;

Tsumeb , nickname = , settlement_type = City , motto = ''Glück Auf'' (German language, German for ''Good luck'') , image_skyline = Welcome to tsumeb.jpg , imagesize = , image_caption ...

, Namibia;

Broken Hill Broken Hill is an inland mining city in the far west of outback New South Wales, Australia. It is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Highway (B79), in the Barrier Range. It is ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

; and

Boleo Figures of Argentine tango are elements of Argentine tango. Introduction and terminology History On the basis of several instructional tango books published between 1911–1925 early tango figures can be grouped into eight categories: corte, pas ...

, near

Santa Rosalía, Baja California Sur Santa Rosalía is a city and municipal seat of Mulegé Municipality, in Baja California Sur, situated along the Gulf of California. Located on the east coast of the Baja Peninsula, the town had a population of 14,160 inhabitants in 2015. The ci ...

. In the US it has been reported from the Terrible mine,

Custer County, Colorado Custer County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 4,704. The county seat is Westcliffe. History Custer County was created by the Colorado legislature on March 9, 1877, out of the southe ...

; the Stevenson-Bennett mine,

Organ Mountains The Organ Mountains (also known as La Sierra de los Órganos) are a rugged mountain range in southern New Mexico in the Southwestern United States. Organ Mountains–Desert Peaks National Monument was declared a national monument on May 21, 2014 ...

Doña Ana County, New Mexico Doña Ana County is located in the southern part of the State of New Mexico, United States. As of the 2020 U.S. Census, its population was 219,561, which makes it the second-most populated county in New Mexico. Its county seat is Las Cruces, th ...

; and the Mammoth mine,

Tiger The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...

Pinal County, Arizona Pinal County is in the central part of the U.S. state of Arizona. According to the 2020 census, the population of the county was 425,264, making it Arizona's third-most populous county. The county seat is Florence. The county was founded in 187 ...

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

References

{{Refend Lead minerals Halide minerals Carbonate minerals Tetragonal minerals Minerals in space group 127 Luminescent minerals