Perovskite

Perovskite crystals have a cubic (pseudo-cubic) shape, the faces of the cubes are dissected by short strokes parallel to the edges. Often crystals are soldered along the faces of cubes. Depending on the impurities, it has a different color: for the most part dark (grayish-black, iron-black, reddish-brown), less often light - hyacinth-red, orange-and-honey-yellow. Perovskite light colors transparent. The hardness according to the mineralogical scale : 5.5 - 6, density : 3.97 - 4.0 g / cm ³ . Calcium can be replaced by Ce , Ti by Nb and Ta , there may be other impurities, which leads to the formation of papitol , disanalite and loparite .

Perovskite was discovered in 1839 in the Ural Mountains by Gustav Rosa and was named after him in honor of the Russian statesman Count L. A. Perovsky , who was a collector of minerals .

Perovskite is found mainly in talc and chlorite schists ; also found in microscopic form in rocks of volcanic origin (in melilite basalt , basalt lava ). Deposits in the Urals , in Tyrol ( Austria ), in Switzerland , in Finland .

Perovskite structure:
A - calcium atom
B - titanium atom
C is an oxygen atom

Perovskite is a source of titanium , niobium and a number of other elements. It is also very famous for its crystalline structure. The titanium atoms in perovskite are located at the sites of a weakly distorted cubic lattice. In the centers of the pseudocubes are calcium atoms. Oxygen atoms form almost regular octahedra around titanium atoms, which are slightly deployed and tilted relative to ideal positions. Among the compounds having the structure of perovskite, oxides , halides , intermetallic compounds . The structure of perovskite (or its derivative) is possessed by high-temperature superconductors , ionic conductors, as well as many magnetic and ferroelectric materials.

The journal Science included perovskite in the top 10 breakthroughs of 2013, implying the possibility of using it in solar energy ^[1] .

It is generally accepted that the lower mantle of the Earth (a layer between the depths of 660 km and 2791 km) consists of 75-80% of the (Mg, Fe) SiO ₃ perovskite-like phase, 5-10% of CaSiO ₃ and 10-15% of magnesium wustite and, therefore, MgSiO ₃ is about half the total volume of our planet (see Ringwood (1991); Ono, Oganov (2005)).

Structurally similar to perovxite, complex polymer bismuth and antimony halides developed by Russian scientists from the A.V. Nikolaev Institute of Inorganic Chemistry SB RAS, the Institute of Problems of Chemical Physics of the Russian Academy of Sciences and affiliated with Skolkovo can become the general principle of building semiconductors for future promising solar cells . This study made it possible to obtain a solar battery with the highest conversion rates of light to electricity for antimony and bismuth halides. ^{[2] [3] [4] [5] [6]} Unlike, for example, the perovxite-like material considered by Chinese ^[7] researchers in 2018, this semiconductor does not contain toxic lead .

• Perovskite in the GeoWiki Encyclopedia (Russian)
• Reference "Minerals of Russia"
• Perovskite in webmineral.com database
• Ringwood, AE - “Phase transformations and their bearing on the constitution and dynamics of the mantle”
• Oganov, AR, Brodholt, JP, Price, GD - “The elastic constants of MgSiO3 perovskite at pressures and temperatures of the Earth's mantle”
• Ono S., Oganov, AR - “In situ observations of phase transition between perovskite and CaIrO3-type phase in MgSiO3 and pyrolitic mantle composition.”