Panethite, chemical formula , is a rare

phosphate mineral Phosphate minerals contain the tetrahedrally coordinated phosphate (PO43−) anion along sometimes with arsenate (AsO43−) and vanadate (VO43−) substitutions, and chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions that also fit i ...

that was only found in one

meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...

on Earth. It was originally found in the Dayton meteorite in

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

. It is classified as H-M symbol (2/m) with space group of ''P''2₁/n. It is amber in color. It was named in the honor of

Friedrich Adolf Paneth Friedrich may refer to: Names *Friedrich (surname), people with the surname ''Friedrich'' *Friedrich (given name), people with the given name ''Friedrich'' Other *Friedrich (board game), a board game about Frederick the Great and the Seven Years' ...

(1887–1958), a German chemist who made many contributions toward the discovery of the origin of the universe, and especially studies of meteorites.

Structure

Using

X-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

, the

unit cell In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...

and the space group parameters were determined. The strongest lines of the X-ray were 5.10(6), 3.236(5), 3.007(10), 2.749, 2.710(7) (American Mineralogist, 509). But the error of the cell lengths were relatively high due to twinning and some disorder in the grains examined. Panethite has a

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

crystal system In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices. Space groups are classified into crystal systems according to their po ...

with a0=10.18 ±0.01Å, b0=14.90 ±0.02Å, c0=25.87 ±0.03Å and β =91.1˚, and its space group P2₁/n. Within the error that accompanied the microprobe analysis, the X-ray density was found to be 2.99g/ml.

Properties

Both

brianite Brianite is a phosphate mineral with the chemical formula Na2CaMg(PO4)2. It was first identified in an iron meteorite. This mineral is named after Brian Harold Mason (1917–2009), a pioneer in meteoritics. It was first reported from the Dayto ...

and panethite were clear and transparent with no crystal faces; and neither present any discernible cleavage. Panethite is a biaxial negative, pale amber in its color and the estimated 2V was approximated to be 51˚. The refractive indices are α=1.567, β=1.576, γ = 1.579 all ±0.001 (Fuchs, 1967). Even though panethite lacks the lamellar structure that brianite shows, panethite shows simple twinning. The higher refractive indices along with the lamellae structure of brianite help us to distinguish these two minerals apart under the microscope. 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 ...

of panethite was between 2.90 and 3.0. Both minerals were insoluble in water. Panethite and brianite are the minerals known to have the greatest amount of sodium content in meteorites (Fuchs, 1967). Panethite was named after the then director of the

Max Planck Institute for Chemistry The Max Planck Institute for Chemistry (Otto Hahn Institute; german: Max Planck Institut für Chemie - Otto Hahn Institut) is a non-university research institute under the auspices of the Max Planck Society (German: Max-Planck-Gesellschaft) in Ma ...

Mainz Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main (river), Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-we ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

, Friedrich Adolf Paneth (1887-1958).

References

*Fuchs, Louis H.(1967) On the occurrence of Brianite and Panethite, two new phosphate minerals from the Dayton meteorite. Geochimica et Cosmochimica Acta, 31, 1711-1719. *Fuchs, Louis H. (1968) Panethite. American Mineralogist, 53, 509 {{Meteorites Phosphate minerals Meteorite minerals Monoclinic minerals Minerals in space group 14

Structure

Properties

See also

References