 | This article or section possibly contains synthesis of material which does not verifiably mention or relate to the main topic.(August 2023) |
In chemistry, a hydridonitride (nitridohydride, nitride hydride, or hydride nitride) is a chemical compound that contains both hydride (H−) and nitride (N3−) ions. These inorganic compounds are distinct from inorganic amides and imides as the hydrogen does not share a bond with nitrogen, and usually contain a larger proportion of metals.[ citation needed ]
The hydride ion H− is stabilised by being surrounded by electropositive elements such as alkalis or alkaline earths. [1] Quaternary compounds exist where nitrogen forms a complex with bonds to a transition or main group element. The hydride requires the presence of another alkaline earth element. [1]
Hydridonitrides may be produced by a process called self-propagating high-temperature synthesis (SHS) where a metal nitride is ignited in a hydrogen atmosphere. [2]
A metal (Ti, Zr, Hf, Y) can also be ignited in an atmosphere mixing hydrogen and nitrogen, and a hydridonitride is formed exothermically. [3]
The molten metal flux technique involves dissolving metal nitrides and hydrides in an excess of molten alkaline earth metal, by heating till everything is molten, and then cooling until crystals form, but the metal is still liquid. Draining the liquid metal (and centrifuging) leaves the crystals of hydridonitride behind. A eutectic molten metal allows it to be cooled more. [1]
If liquid alkali metal is used as a flux to grow a hydridonitride crystal, excess metal can be removed using liquid ammonia. [4]
Some hydridonitrides are sensitive to water vapour in air. [5] For non-stoichimetric compounds, as the proportion of hydrogen increases, the unit cell dimensions also increase, so hydrogen is not merely filling holes. [6] When heated to a sufficiently high temperature, hydridonitrides lose hydrogen first to form a metallic nitride or alloy. [7]
One lutetium hydride doped with nitrogen is claimed to be a room-temperature superconductor at up to 21°C at a pressure of 1 GPa, which is considerably lower than for other polyhydrides. [8] This has been called "red matter" [9] as it is red under high pressure, but blue at ambient conditions. [10] [11] The claim has been met with some skepticism as it was made by the same team that made similar claims retracted by Nature in 2022, [12] [13] [14] [15] [16] claimed observation of solid metallic hydrogen in 2016 as well as other allegations. [17] First attempts to replicate the results have failed. [18] [19] Ashcroft suggested metallic hydrogen could superconduct in 1968 [20] at great pressures and in 2004 similarly that dense group IVa hydrides (as the new material) could also be superconductors at more accessible pressures. [21]
| name | formula | system | space group | unit cell (lengths in Å, volume in Å3) | structure | comment | optical | reference |
|---|---|---|---|---|---|---|---|---|
| Lithium nitride hydride Lithium hydridonitride | Li4NH | tetragonal | I41/a | a = 4.9865, c = 9.877, V = 234.9, Z = 4 | yellow | [4] | ||
| calcium hydridonitride | Ca2NH | cubic | Fd3m | a = 10.13, Z = 16 | brown-black | [5] | ||
| tricalcium silicon trinitride hydride | Ca3SiN3H | monoclinic | C2/c | a = 5.236, b = 10.461, c = 16.389, β = 91.182°, Z = 8 | SiN4 tetrahedra in chains, Ca6H octahedra | [1] [22] | ||
| Titanium hydridonitride | TiN0.3H1.1 | [6] | ||||||
| Ti0.7V0.3N0.23H0.8 | [6] | |||||||
| Ca3CrN3H | hexagonal | P63/m | a= 7.22772 c=5.06172 Z=2 V=228.998 | [23] | ||||
| hexacalcium dichromium hexanitride hydride | Ca6Cr2N6H | R3 | a = 9.0042, c = 9.1898, Z = 3 | planar CrN6−3, CrN5−3, octahedral Ca6H11+ | [1] [24] | |||
| strontium hydridonitride | Sr2NH | R3m | a = 3.870, c = 18.958 | orange-yellow or black | [25] | |||
| Lithium distrontium dihydride nitride | LiSr2H2N | orthorhombic | Pnma | a = 7.4714, b = 3.7028, c = 13.2986, Z = 4 | [SrH5N2]9−, [SrH4N3]11−, [LiH3N]5− | [26] | ||
| Ti0.6Nb0.4N0.4H1.1 | [6] | |||||||
| zirconium hydridonitride | ZrN0.17H1.65 | [2] | ||||||
| Ti0.88Zr0.12N0.28H1.39 | [6] | |||||||
| Zr0.7Nb0.3N0.33H1.15 | [6] | |||||||
| barium hydridonitride | Ba2NH | hexagonal | R3m | a = 4.0262, c = 20.469 | pure H− conductor | [27] | ||
| Tribarium chromium trinitride hydride | Ba3CrN3H | hexagonal | P63/m | a = 8.0270, c = 5.6240, Z = 2 V=313.83 | planar CrN5−3, octahedral HBa11+6 | nonmagnetic insulator | green | [28] [29] [1] |
| Lithium dieuropium nitride trihydride | LiEu2NH3 | orthorhombic | Pnma | a = 7.4213, b = 3.6726, c = 13.1281, Z = 4 | [Eu3+H7N2]10− and [Eu2+H6N3]13− | ruby red | [30] | |
| Lutetium hydride nitride | LuH3−xNy | Fm3m | < 1 GPa | blue | [31] [8] | |||
| Lutetium hydride nitride | LuH3−xNy | Immm | super conductor at 1 GPa and 21 °C | pink | [8] | |||
| Hafnium hydridonitride | HfNH0.6 | hcp | a = 3.241, c = 5.198 | [7] | ||||
| Hafnium hydridonitride | HfNH | hcp | a = 3.216, c = 5.259 | [7] | ||||
| Thorium nitride hydride | ThNH2 | fcc | a = 5.596 | [32] |
Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered, even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source.
High-temperature superconductors are defined as materials with critical temperature above 77 K, the boiling point of liquid nitrogen. They are only "high-temperature" relative to previously known superconductors, which function at even colder temperatures, close to absolute zero. The "high temperatures" are still far below ambient, and therefore require cooling. The first break through of high-temperature superconductor was discovered in 1986 by IBM researchers Georg Bednorz and K. Alex Müller. Although the critical temperature is around 35.1 K, this new type of superconductor was readily modified by Ching-Wu Chu to make the first high-temperature superconductor with critical temperature 93 K. Bednorz and Müller were awarded the Nobel Prize in Physics in 1987 "for their important break-through in the discovery of superconductivity in ceramic materials". Most high-Tc materials are type-II superconductors.
Metallic hydrogen is a phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington.
Palladium hydride is palladium metal with hydrogen within its crystal lattice. Despite its name, it is not an ionic hydride but rather an alloy of palladium with metallic hydrogen that can be written PdHx. At room temperature, palladium hydrides may contain two crystalline phases, α and β. Pure α-phase exists at x < 0.017 while pure β-phase exists at x > 0.58; intermediate x values correspond to α-β mixtures.
A room-temperature superconductor is a hypothetical material capable of displaying superconductivity at temperatures above 0 °C, which are commonly encountered in everyday settings. As of 2023, the material with the highest accepted superconducting temperature was highly pressurized lanthanum decahydride, whose transition temperature is approximately 250 K (−23 °C) at 200 GPa.
In chemistry, a nitride is a chemical compound of nitrogen. Nitrides can be inorganic or organic, ionic or covalent. The nitride anion, N3- ion, is very elusive but compounds of nitride are numerous, although rarely naturally occurring. Some nitrides have a found applications, such as wear-resistant coatings (e.g., titanium nitride, TiN), hard ceramic materials (e.g., silicon nitride, Si3N4), and semiconductors (e.g., gallium nitride, GaN). The development of GaN-based light emitting diodes was recognized by the 2014 Nobel Prize in Physics. Metal nitrido complexes are also common.
Lithium nitride is an inorganic compound with the chemical formula Li3N. It is the only stable alkali metal nitride. It is a reddish-pink solid. It has high melting point.
Mikhail Ivanovich Eremets is an experimentalist in high pressure physics, chemistry and materials science. He is particularly known for his research on superconductivity, having discovered the highest critical temperature of 250 K (-23 °C) for superconductivity in lanthanum hydride under high pressures. Part of his research contains exotic manifestations of materials such as conductive hydrogen, polymeric nitrogen and transparent sodium.
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 FeH5, LiH6, and LiH7. By contrast, the more well known lithium hydride only has one hydrogen atom.
Lanthanum decahydride is a polyhydride or superhydride compound of lanthanum and hydrogen (LaH10) that has shown evidence of being a high-temperature superconductor. It was the first metal superhydride to be theoretically predicted, synthesized, and experimentally confirmed to superconduct at near room-temperatures. It has a superconducting transition temperature TC around 250 K (−23 °C; −10 °F) at a pressure of 150 gigapascals (22×106 psi), and its synthesis required pressures above approximately 160 gigapascals (23×106 psi).
An oxyhydride is a mixed anion compound containing both oxide O2− and hydride ions H−. These compounds may be unexpected as the hydrogen and oxygen could be expected to react to form water. But if the metals making up the cations are electropositive enough, and the conditions are reducing enough, solid materials can be made that combine hydrogen and oxygen in the negative ion role.
Carbohydrides are solid compounds in one phase composed of a metal with carbon and hydrogen in the form of carbide and hydride ions. The term carbohydride can also refer to a hydrocarbon.
The inorganic imide is an inorganic chemical compound containing
An arsenide hydride or hydride arsenide is a chemical compound containing hydride (H−) and arsenide (As3−) ions in a single phase. They are in the class of mixed anion compounds.
Carbonaceous sulfur hydride (CSH) is a potential superconductor that was announced in October 2020 by the lab of Ranga Dias at the University of Rochester, in a Nature paper that was later retracted. It was reported to have a superconducting transition temperature of 15 °C (59 °F) at a pressure of 267 gigapascals (GPa), which would have made it the highest-temperature superconductor discovered. The paper faced criticism dut to its non-standard data analysis calling into question its conclusions, and in September 2022 it was retracted by Nature. In July 2023 a second paper by the authors was retracted from Physical Review Letters due to suspected data fabrication, and in September 2023 a third paper by the authors about N-doped lutetium hydride was retracted from Nature.
A chloride nitride is a mixed anion compound containing both chloride (Cl−) and nitride ions (N3−). Another name is metallochloronitrides. They are a subclass of halide nitrides or pnictide halides.
Arsenide nitrides or nitride arsenides are compounds containing anions composed of nitride (N3−) and arsenide (As3−). They can be considered as mixed anion compounds or mixed pnictide compounds. Related compounds include the arsenide phosphides, germanide arsenides, arsenide carbides, and phosphide nitrides.
An iodide nitride is a mixed anion compound containing both iodide (I−) and nitride ions (N3−). Another name is metalloiodonitrides. They are a subclass of halide nitrides or pnictide halides. Some different kinds include ionic alkali or alkaline earth salts, small clusters where metal atoms surround a nitrogen atom, layered group 4 element 2-dimensional structures, and transition metal nitrido complexes counter-balanced with iodide ions. There is also a family with rare earth elements and nitrogen and sulfur in a cluster.
Ranga P. Dias is a researcher and academic who specializes in condensed matter physics. He is an assistant professor in the departments of Mechanical Engineering and Physics and Astronomy at the University of Rochester (UR), and a scientist at the UR Laboratory for Laser Energetics.