Calcium titanate
Encyclopedia
Perovskite is a calcium titanium oxide mineral
species composed of calcium titanate
, with the chemical formula Ca
Ti
O
3.
The mineral was discovered in the Ural Mountains
of Russia
by Gustav Rose
in 1839 and is named after Russian mineralogist Lev Perovski
(1792–1856).
It lends its name to the class of compounds which have the same type of crystal structure
as CaTiO3 (XIIA2+VIIB4+X2–3) known as the perovskite structure. The perovskite crystal structure was published in 1945 from X-ray diffraction data on barium titanate
by the Irish crystallographer Helen Dick Megaw (1907–2002).
s at Magnet Cove
, Arkansas
. It occurs in altered blocks of limestone
ejected from Mount Vesuvius
. It occurs in chlorite
and talc
schist
in the Urals and Switzerland
. It is also found as an accessory mineral in alkaline and mafic
igneous rock
s, nepheline syenite
, melilitite, kimberlite
s and rare carbonatite
s. Perovskite is a common mineral in the Ca-Al-rich inclusions found in some chondritic meteorite
s.
A rare earth
-bearing variety, knopite, (Ca,Ce,Na)(Ti,Fe)O3) is found in alkali intrusive rocks in the Kola Peninsula
and near Alnö, Sweden
. A niobium
-bearing variety, dysanalyte, occurs in carbonatite
near Schelingen, Kaiserstuhl
, Germany
.
.
, colorless streak
, cube like structure along with imperfect cleavage
and brittle tenacity are physical properties
of perovskite. Colors range from black, brown, gray, orange to yellow. Crystals of perovskite appear as cubes, but are pseudocubic and crystallize in the orthorhombic system. Perovskite crystals have been mistaken for galena
, however galena has a better metallic luster, greater density, perfect cleavage and true cubic symmetry.
Physical properties of interest to materials science
among perovskites include superconductivity
, magnetoresistance
, ionic conductivity
, and a multitude of dielectric properties, which are of great importance in microelectronics and telecommunication
. Because of the flexibility of bond angles inherent in the perovskite structure there are many different types of distortions which can occur from the ideal structure. These include tilting of the octahedra, displacements of the cations out of the centers of their coordination polyhedra, and distortions of the octahedra driven by electronic
factors (Jahn-Teller distortions).
, the perovskite’s occurrence at Khibina Massif is restricted to the under saturated ultramafic rocks and foidolite
s, due to the instability in a paragenesis
with feldspar
. The complexity is made by an extended series of rocks from early alkaline ultramafic members to late carbonatites that comprise alkaline and mafic igneous rocks such as nepheline syenite
, melilitite, kimberlite
and rare carbonatites in ultramafites. Perovskite occurs as small anhedral
to subhedral crystals filling interstices between the rock-forming silicates.
, Southern Urals
, Russia. The new mineral was named by Gustav Rose
for Russian mineralogist, Count Lev Alekseevich Perovski
(1792–1856), of St. Petersburg, Russia.
Oxide mineral
The oxide mineral class includes those minerals in which the oxide anion is bonded to one or more metal ions. The hydroxide bearing minerals are typically included in the oxide class...
species composed of calcium titanate
Calcium titanate
Perovskite is a calcium titanium oxide mineral species composed of calcium titanate, with the chemical formula CaTiO3.The mineral was discovered in the Ural Mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist Lev Perovski .It lends its name to the class of compounds...
, with the chemical formula Ca
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
Ti
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
O
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....
3.
The mineral was discovered in the Ural Mountains
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
by Gustav Rose
Gustav Rose
Gustav Rose was a German mineralogist who was a native of Berlin. He was a brother of mineralogist Heinrich Rose , the son of pharmacologist Valentin Rose , and the father of noted surgeon Edmund Rose and the classicist Valentin Rose.He was a graduate of the University of Berlin, where he was a...
in 1839 and is named after Russian mineralogist Lev Perovski
Lev Perovski
Count Lev Aleksevich von Perovski was a Russian nobleman and mineralogist who also served as Minister of Internal Affairs under Nicholas I of Russia....
(1792–1856).
It lends its name to the class of compounds which have the same type of crystal structure
Crystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
as CaTiO3 (XIIA2+VIIB4+X2–3) known as the perovskite structure. The perovskite crystal structure was published in 1945 from X-ray diffraction data on barium titanate
Barium titanate
Barium titanate is the inorganic compound with the chemical formula BaTiO3. Barium titanate is a white powder and transparent as larger crystals...
by the Irish crystallographer Helen Dick Megaw (1907–2002).
Occurrence
Perovskite is found in contact carbonate skarnSkarn
Skarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...
s at Magnet Cove
Magnet Cove igneous complex
The Magnet Cove igneous complex is a small alkalic ring complex lying to the west of the town of Magnet Cove in Hot Spring County, Arkansas. It and the adjacent town are so named due to the existence of magnetite and the terrain being a cove, a basin-shaped valley.The complex is of Mesozoic age,...
, Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
. It occurs in altered blocks of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
ejected from Mount Vesuvius
Mount Vesuvius
Mount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting...
. It occurs in chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....
and talc
Talc
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its crystals being so rare as to be almost unknown...
schist
Schist
The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is...
in the Urals and Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
. It is also found as an accessory mineral in alkaline and mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...
igneous rock
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...
s, nepheline syenite
Nepheline syenite
Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are also known...
, melilitite, kimberlite
Kimberlite
Kimberlite is a type of potassic volcanic rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an diamond in 1871 spawned a diamond rush, eventually creating the Big Hole....
s and rare carbonatite
Carbonatite
Carbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....
s. Perovskite is a common mineral in the Ca-Al-rich inclusions found in some chondritic meteorite
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...
s.
A rare earth
Rare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
-bearing variety, knopite, (Ca,Ce,Na)(Ti,Fe)O3) is found in alkali intrusive rocks in the Kola Peninsula
Kola Peninsula
The Kola Peninsula is a peninsula in the far northwest of Russia. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely to the north of the Arctic Circle and is washed by the Barents Sea in the north and the White Sea in the east and southeast...
and near Alnö, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. A niobium
Niobium
Niobium or columbium , is a chemical element with the symbol Nb and atomic number 41. It's a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite...
-bearing variety, dysanalyte, occurs in carbonatite
Carbonatite
Carbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....
near Schelingen, Kaiserstuhl
Kaiserstuhl
The „Kaiserstuhl“ is a relatively low mountain range – a Mittelgebirge – with a maximal height of 556.6 m above sea level. It is of volcanic origin and located in the South West of Baden-Württemberg, Germany in the districts of Emmendingen and Breisgau-Hochschwarzwald...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.
Special characteristics
The stability of perovskite in igneous rocks is limited by its reaction relation with sphene. In volcanic rocks perovskite and sphene are not found together, the only exception being in an atindite from CamerounCameroun
Cameroun was a French and British mandate territory in central Africa, now constituting the majority of the territory of the Republic of Cameroon....
.
Physical properties
The sub-metallic to metallic lusterLustre (mineralogy)
Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....
, colorless streak
Streak (mineralogy)
The streak of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus...
, cube like structure along with imperfect cleavage
Cleavage (crystal)
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...
and brittle tenacity are physical properties
Physical property
A physical property is any property that is measurable whose value describes a physical system's state. The changes in the physical properties of a system can be used to describe its transformations ....
of perovskite. Colors range from black, brown, gray, orange to yellow. Crystals of perovskite appear as cubes, but are pseudocubic and crystallize in the orthorhombic system. Perovskite crystals have been mistaken for galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
, however galena has a better metallic luster, greater density, perfect cleavage and true cubic symmetry.
Physical properties of interest to materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...
among perovskites include superconductivity
Superconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
, magnetoresistance
Magnetoresistance
Magnetoresistance is the property of a material to change the value of its electrical resistance when an external magnetic field is applied to it. The effect was first discovered by William Thomson in 1856, but he was unable to lower the electrical resistance of anything by more than 5%. This...
, ionic conductivity
Ionic conductivity
Ionic conduction is the movement of an ion from one site to another through defects in the crystal lattice of a solid. Ionic conduction is one aspect of current....
, and a multitude of dielectric properties, which are of great importance in microelectronics and telecommunication
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
. Because of the flexibility of bond angles inherent in the perovskite structure there are many different types of distortions which can occur from the ideal structure. These include tilting of the octahedra, displacements of the cations out of the centers of their coordination polyhedra, and distortions of the octahedra driven by electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
factors (Jahn-Teller distortions).
Geologic occurrence
Basically found in the earth’s mantleMantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
, the perovskite’s occurrence at Khibina Massif is restricted to the under saturated ultramafic rocks and foidolite
Foidolite
Foidolite is a rare coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%. Crystals of alkali feldspar, plagioclase, biotite, amphibole, pyroxene and/or olivine may be present within the rock...
s, due to the instability in a paragenesis
Paragenesis
Paragenesis is a petrologic concept meaning an equilibrium assemblage of mineral phases. It is used in studies of igneous and metamorphic rock genesis and importantly in studies of the hydrothermal deposition of ore minerals and the rock alteration associated with ore mineral deposits...
with feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....
. The complexity is made by an extended series of rocks from early alkaline ultramafic members to late carbonatites that comprise alkaline and mafic igneous rocks such as nepheline syenite
Nepheline syenite
Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are also known...
, melilitite, kimberlite
Kimberlite
Kimberlite is a type of potassic volcanic rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an diamond in 1871 spawned a diamond rush, eventually creating the Big Hole....
and rare carbonatites in ultramafites. Perovskite occurs as small anhedral
Anhedral
* Anhedral angle, the downward angle from horizontal of the wings or tailplane of a fixed-wing aircraft* Anhedral , a rock texture without crystal faces or cross-section shape in thin section...
to subhedral crystals filling interstices between the rock-forming silicates.
Discovery and name
Perovskite was first described in 1839 from an occurrence in the Achmatovsk Mine in the Nazyamskie Mountains, Chelyabinsk OblastChelyabinsk Oblast
-External links:*...
, Southern Urals
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
, Russia. The new mineral was named by Gustav Rose
Gustav Rose
Gustav Rose was a German mineralogist who was a native of Berlin. He was a brother of mineralogist Heinrich Rose , the son of pharmacologist Valentin Rose , and the father of noted surgeon Edmund Rose and the classicist Valentin Rose.He was a graduate of the University of Berlin, where he was a...
for Russian mineralogist, Count Lev Alekseevich Perovski
Lev Perovski
Count Lev Aleksevich von Perovski was a Russian nobleman and mineralogist who also served as Minister of Internal Affairs under Nicholas I of Russia....
(1792–1856), of St. Petersburg, Russia.