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Iron Pentahydride
Iron pentahydride is a polyhydride, superhydride compound of iron and hydrogen, stable under high pressures. It is important because it contains atomic hydrogen atoms that are not bonded into smaller molecular clusters, and may be a superconductor. Pairs of hydrogen atoms are not bonded together into molecules. has been made by compressing a flake of iron with hydrogen in a diamond anvil cell to a pressure of 130 GPa and heating to below 1500K. When decompressed to 66 GPa it decomposes to solid iron trihydride, . The unit cell is tetragonal crystal system, tetragonal with space group ''I''4/''mmm''. See also *Iron hydrides References {{inorganic-compound-stub Hydrides Iron compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyhydride
A polyhydride or superhydride is a compound that contains an abnormally large amount of hydrogen. This can be described as high hydrogen stoichiometry. Examples include iron pentahydride , , and . By contrast, the more well known lithium hydride only has one hydrogen atom. Polyhydrides are only known to be stable under high pressure. Polyhydrides are important because they can form substances with a very high density of hydrogen. They may resemble the elusive metallic hydrogen, but can be made under lower pressures. One possibility is that they could be superconductors. Hydrogen sulfide under high pressures forms units, and can be a superconductor at and a pressure of 1.5 million Atmosphere (unit), atmospheres (152 GPa). Structures The polyhydrides of Alkaline earth metal, alkaline earth and alkali metals contain cage structures. Also hydrogen may be clustered into , , or units. Polyhydrides of transition metals may have the hydrogen atoms arranged around the metal atom. Comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter. Under standard conditions, hydrogen is a gas of diatomic molecules with the chemical formula, formula , called dihydrogen, or sometimes hydrogen gas, molecular hydrogen, or simply hydrogen. Dihydrogen is colorless, odorless, non-toxic, and highly combustible. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found as the gas (dihydrogen) and in molecular forms, such as in water and organic compounds. The most common isotope of hydrogen (H) consists of one proton, one electron, and no neutrons. Hydrogen gas was first produced artificially in the 17th century by the reaction of acids with metals. Henry Cavendish, in 1766–1781, identified hydrogen gas as a distinct substance and discovere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Anvil Cell
A diamond anvil cell (DAC) is a high-pressure device used in geology, engineering, and materials science experiments. It permits the compression of a small (sub- millimeter-sized) piece of material to extreme pressures, typically up to around 100–200 gigapascals, although it is possible to achieve pressures up to 770 gigapascals (7,700,000 bars or 7.7 million atmospheres). The device has been used to recreate the pressure existing deep inside planets to synthesize materials and phases not observed under normal ambient conditions. Notable examples include the non-molecular ice X, polymeric nitrogen and metallic phases of xenon, lonsdaleite, and potentially metallic hydrogen. A DAC consists of two opposing diamonds with a sample compressed between the polished culets (tips). Pressure may be monitored using a reference material whose behavior under pressure is known. Common pressure standards include ruby fluorescence, and various structurally simp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Trihydride
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechanical prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragonal Crystal System
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 base (''a'' by ''a'') and height (''c'', which is different from ''a''). Bravais lattices There are two tetragonal Bravais lattices: the primitive tetragonal and the body-centered tetragonal. The body-centered tetragonal lattice is equivalent to the primitive tetragonal lattice with a smaller unit cell, while the face-centered tetragonal lattice is equivalent to the body-centered tetragonal lattice with a smaller unit cell. Crystal classes The point groups that fall under this crystal system are listed below, followed by their representations in international notation, Schoenflies notation, orbifold notation, Coxeter notation and mineral examples.Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Hydride
An iron hydride is a chemical system which contains iron and hydrogen in some associated form. Because of the common occurrence of those two element (chemistry), elements in the universe, possible compounds of hydrogen and iron have attracted attention. A few molecular compounds have been detected in extreme environments (such as stellar atmospheres) or in small amounts at very low temperatures. The two elements form a metallic alloy above of pressure, that has been advanced as a possible explanation for the low density of inner core, Earth's "iron" core. However those compounds are unstable when brought to ambient conditions, and eventually decompose into the separate elements. Small amounts of hydrogen (up to about 0.08% by weight) are absorbed into iron as it solidifies from its molten state. Although the H2 is simply an impurity, its presence can affect the material's mechanical properties. Despite the fleeting nature of binary iron hydrides, there are many fairly stable h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrides
In chemistry, a hydride is formally the anion of hydrogen (H−), a hydrogen ion with two electrons. In modern usage, this is typically only used for ionic bonds, but it is sometimes (and has been more frequently in the past) applied to all compounds containing covalently bound H atoms. In this broad and potentially archaic sense, water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. In covalent compounds, it implies hydrogen is attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed. Almost all of the elements form binary compounds with hydrogen, the exceptions being He, Ne, Ar, Kr, Pm, Os, Ir, Rn, Fr, and Ra. Exotic molecules such as positronium hydride have also been made. Bonds Bonds between hydrogen and the other elements range from being highly ionic to somewhat covalent. Some hydrides, e.g. boro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
