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Changbaiite
Changbaiite (PbNb2O6) is a member of the oxide mineral class in which the mineral contains oxygen which is grouped along with one or two metal ion. Changbaiite is classified as a multiple Oxide XY2O6 and it generally has an ionic bond. Furthermore, it is also orthorhombic at a temperature of 25 °C and it changes to orthorhombic-tetragonal at 570 °C.Subbarao, E. C., and Shirane, G. (1960) "Nonstoichiometry and Ferroelectric Properties of PbNb2O6-Type Compounds". ''Journal of Chemical Physics', 32, 1846–1851Ferroelectric Properties of PbNb2O6-Type Compounds/ref> Composition The chemical formula of changbaiite is PbNb2O6 after microprobe analysis of kaolinite-filled veins. It is composed of iron (II) oxide FeO 0.94%, lead oxide PbO 41.51%, iron (III) oxide Fe2O3 0.42%, titanium dioxide TiO2 0.95%, niobium pentoxide Nb2O5 55.62%, and tantalum pentoxide Ta2O5 0.98%, which produce the chemical formula (Pb0.95Fe2+0.05)(Nb1.95Ti0.05Fe3+0.02Ta0.01) or PbNb2O6. It was also exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide Minerals
The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. The minerals with complex anion groups such as the silicates, sulfates, carbonates and phosphates are classed separately. Simple oxides: *XO **Periclase group ***Periclase ***Manganosite **Zincite group ***Zincite *** Bromellite ***Tenorite ***Litharge * **Cuprite **Ice * **Hematite group ***Corundum ***Hematite ***Ilmenite * **Rutile group ***Rutile ***Pyrolusite *** Cassiterite ** Baddeleyite **Uraninite **Thorianite * **Spinel group ***Spinel ***Gahnite ***Magnetite ***Franklinite *** Chromite **Chrysoberyl **Columbite *Hydroxide subgroup: **Brucite **Manganite ** Romanèchite **Goethite group: ***Diaspore ***Goethite Nickel–Strunz Classification -04- Oxides IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 2009). This list uses it to mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide Mineral
The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. The minerals with complex anion groups such as the silicates, sulfates, carbonates and phosphates are classed separately. Simple oxides: *XO **Periclase group ***Periclase ***Manganosite **Zincite group ***Zincite *** Bromellite ***Tenorite ***Litharge * **Cuprite **Ice * **Hematite group ***Corundum ***Hematite ***Ilmenite * **Rutile group ***Rutile ***Pyrolusite ***Cassiterite **Baddeleyite **Uraninite **Thorianite * **Spinel group ***Spinel ***Gahnite ***Magnetite ***Franklinite ***Chromite **Chrysoberyl **Columbite *Hydroxide subgroup: **Brucite **Manganite ** Romanèchite **Goethite group: ***Diaspore ***Goethite Nickel–Strunz Classification -04- Oxides IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 2009). This list uses it to modify ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tantalum Pentoxide
Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula . It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid. is an inert material with a high refractive index and low absorption (i.e. colourless), which makes it useful for coatings. It is also extensively used in the production of capacitors, due to its high dielectric constant. Preparation Occurrence Tantalum occurs in the minerals tantalite and columbite (columbium being an archaic name for niobium), which occur in pegmatites, an igneous rock formation. Mixtures of columbite and tantalite are called coltan. Tantalite was discovered by Anders Gustaf Ekeberg at Ytterby, Sweden, and Kimoto, Finland. The minerals microlite and pyrochlore contain approximately 70% and 10% Ta, respectively. Refining Tantalum ores often contain significant amounts of niobium, which is itself a valuable metal. As such, both metals are extracted so that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonal
In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crystal system and the rhombohedral lattice system are not equivalent (see section crystal systems below). In particular, there are crystals that have trigonal symmetry but belong to the hexagonal lattice (such as α-quartz). The hexagonal crystal family consists of the 12 point groups such that at least one of their space groups has the hexagonal lattice as underlying lattice, and is the union of the hexagonal crystal system and the trigonal crystal system. There are 52 space groups associated with it, which are exactly those whose Bravais lattice is either hexagonal or rhombohedral. __TOC__ Lattice systems The hexagonal crystal family consists of two lattice systems: hexagonal and rhombohedral. Each lattice system consists of one Bravais l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Number
In chemistry, crystallography, and materials science, the coordination number, also called ligancy, of a central atom in a molecule or crystal is the number of atoms, molecules or ions bonded to it. The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. This number is determined somewhat differently for molecules than for crystals. For molecules and polyatomic ions the coordination number of an atom is determined by simply counting the other atoms to which it is bonded (by either single or multiple bonds). For example, r(NH3)2Cl2Br2sup>− has Cr3+ as its central cation, which has a coordination number of 6 and is described as ''hexacoordinate''. The common coordination numbers are 4, 6 and 8. Molecules, polyatomic ions and coordination complexes In chemistry, coordination number, defined originally in 1893 by Alfred Werner, is the total number of neighbors of a central atom in a molecule or ion. The concept is most commonly applied to coordin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octahedral
In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. A regular octahedron is the dual polyhedron of a cube. It is a rectified tetrahedron. It is a square bipyramid in any of three orthogonal orientations. It is also a triangular antiprism in any of four orientations. An octahedron is the three-dimensional case of the more general concept of a cross polytope. A regular octahedron is a 3-ball in the Manhattan () metric. Regular octahedron Dimensions If the edge length of a regular octahedron is ''a'', the radius of a circumscribed sphere (one that touches the octahedron at all vertices) is :r_u = \frac a \approx 0.707 \cdot a and the radius of an inscribed sphere (tangent to each of the octahedron's faces) is :r_i = \frac a \approx 0.408\cdot a while the midradius, which t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Changbai Mountains
The Changbai Mountains (simplified Chinese:长白山; traditional Chinese:長白山) are a major mountain range in Northeast Asia that extends from the Northeast Chinese provinces of Heilongjiang, Jilin and Liaoning, across the border between China and North Korea (41°41' to 42°51'N; 127°43' to 128°16'E), to the North Korean provinces of Ryanggang and Chagang. They are also referred to as the Šanggiyan Mountains in Manchu. Most peaks exceed in height． History The mountain was first recorded in the ''Classic of Mountains and Seas'' under the name Buxian Shan (). It is also called Shanshan Daling () in the ''Book of the Later Han''. In the ''New Book of Tang'', it was called Taibai Shan ().Second Canonical Book of the Tang Dynasty. (English translation: Khitan general Li Jinzhong killed Zhao Hui, the commanding officer of Yin Zhou. Officer Dae Jung-sang, with Mohe chieftain Qisi Piyu and Goguryeo remnants, escaped to the east, crossed Liao River, guarded the northeast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jilin
Jilin (; alternately romanized as Kirin or Chilin) is one of the three provinces of Northeast China. Its capital and largest city is Changchun. Jilin borders North Korea (Rasŏn, North Hamgyong, Ryanggang and Chagang) and Russia (Primorsky Krai) to the east, Heilongjiang to the north, Liaoning to the south, and Inner Mongolia to the west. Along with the rest of Northeast China, Jilin underwent an early period of industrialization. However, Jilin's economy, characterized by heavy industry, has been facing economic difficulties with privatization. This prompted the central government to undertake a campaign called "Revitalize the Northeast". The region contains large deposits of oil shale. Name The name "Jilin" originates from ''girin ula'' () , a Manchu phrase meaning "along the river", shortened to Kirin in English. This Manchu term was transcribed into ''jilin wula'' ( t , s ) in Chinese characters and shortened the first two characters, which are tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonghua
Tonghua () is a prefecture-level city in the south of Jilin province, People's Republic of China. It borders North Korea's Chagang Province to the south and southeast, Baishan to the east, Jilin City to the north, Liaoyuan to the northwest, and Liaoning province to the west and southwest. Its population was 1,812,114 registered residents at the 2020 census living in an area of . its built-up (or metro) area made of the two urban districts was home to 446,917 inhabitants. It is known as one of the five medicine production centres in China. History Human settlement in the Tonghua area dates from about 6000 years ago. In the Western Han Dynasty, Tonghua belonged to the Liaodong Fourth Commandery (). Tonghua was the birthplace of Goguryeo culture and shaman culture. The Goguryeo kingdom established its capital at Gungnae in 425 A.D., which, together with the Tombs of the Ancient Gogoryeo Kingdom, represents the only successful, independent submission to become a UNESCO World Her ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the continental crust of Earth, where it is found in igneous intrusions. These range in size from dikes only a few centimeters across to batholiths exposed over hundreds of square kilometers. Granite is typical of a larger family of ''granitic rocks'', or ''granitoids'', that are composed mostly of coarse-grained quartz and feldspars in varying proportions. These rocks are classified by the relative percentages of quartz, alkali feldspar, and plagioclase (the QAPF classification), with true granite representing granitic rocks rich in quartz and alkali feldspar. Most granitic rocks also contain mica or amphibole minerals, though a few (known as leucogranites) contain almost no dark minerals. Granite is nearly alway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
