Identifiers | |
---|---|
3D model (JSmol) | |
| |
| |
Properties | |
US | |
Molar mass | 270.095 g/mol |
Melting point | 2460 °C [1] |
Structure [1] | |
NaCl type (cubic) | |
Fm3m (No. 225) | |
a = 548.66 pm | |
Formula units (Z) | 4 |
Related compounds | |
Other anions | Uranium carbide Uranium monophosphide |
Related compounds | Uranium disulfide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Uranium monosulfide (US) is an inorganic chemical compound of uranium and sulfur. [2]
Magnetically, the compound is paramagnetic at room temperature, with a Curie Temperature of 180 K. [3] It has the largest known magnetocrystalline anisotropy of any cubic system. [4]
Ferromagnetism is a property of certain materials that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagnetic materials are familiar metals that are noticeably attracted to a magnet, a consequence of their substantial magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an external magnetic field. This temporarily induced magnetization, for example, inside a steel plate, accounts for its attraction to the permanent magnet. Whether or not that steel plate acquires a permanent magnetization itself depends not only on the strength of the applied field but on the so-called coercivity of the ferromagnetic material, which can vary greatly.
Samarium is a chemical element; it has symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide.
A single-molecule magnet (SMM) is a metal-organic compound that has superparamagnetic behavior below a certain blocking temperature at the molecular scale. In this temperature range, a SMM exhibits magnetic hysteresis of purely molecular origin. In contrast to conventional bulk magnets and molecule-based magnets, collective long-range magnetic ordering of magnetic moments is not necessary.
Exchange bias or exchange anisotropy occurs in bilayers of magnetic materials where the hard magnetization behavior of an antiferromagnetic thin film causes a shift in the soft magnetization curve of a ferromagnetic film. The exchange bias phenomenon is of tremendous utility in magnetic recording, where it is used to pin the state of the readback heads of hard disk drives at exactly their point of maximum sensitivity; hence the term "bias."
Copper monosulfide is a chemical compound of copper and sulfur. It was initially thought to occur in nature as the dark indigo blue mineral covellite. However, it was later shown to be rather a cuprous compound, formula Cu+3S(S2). CuS is a moderate conductor of electricity. A black colloidal precipitate of CuS is formed when hydrogen sulfide, H2S, is bubbled through solutions of Cu(II) salts. It is one of a number of binary compounds of copper and sulfur (see copper sulfide for an overview of this subject), and has attracted interest because of its potential uses in catalysis and photovoltaics.
Uranium dioxide or uranium(IV) oxide , also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used as MOX fuel. Prior to 1960, it was used as yellow and black color in ceramic glazes and glass.
The A15 phases (also known as β-W or Cr3Si structure types) are series of intermetallic compounds with the chemical formula A3B (where A is a transition metal and B can be any element) and a specific structure. The A15 phase is also one of the members in the Frank–Kasper phases family. Many of these compounds have superconductivity at around 20 K (−253 °C; −424
A spin ice is a magnetic substance that does not have a single minimal-energy state. It has magnetic moments (i.e. "spin") as elementary degrees of freedom which are subject to frustrated interactions. By their nature, these interactions prevent the moments from exhibiting a periodic pattern in their orientation down to a temperature much below the energy scale set by the said interactions. Spin ices show low-temperature properties, residual entropy in particular, closely related to those of common crystalline water ice. The most prominent compounds with such properties are dysprosium titanate (Dy2Ti2O7) and holmium titanate (Ho2Ti2O7). The orientation of the magnetic moments in spin ice resembles the positional organization of hydrogen atoms (more accurately, ionized hydrogen, or protons) in conventional water ice (see figure 1).
A quantum critical point is a point in the phase diagram of a material where a continuous phase transition takes place at absolute zero. A quantum critical point is typically achieved by a continuous suppression of a nonzero temperature phase transition to zero temperature by the application of a pressure, field, or through doping. Conventional phase transitions occur at nonzero temperature when the growth of random thermal fluctuations leads to a change in the physical state of a system. Condensed matter physics research over the past few decades has revealed a new class of phase transitions called quantum phase transitions which take place at absolute zero. In the absence of the thermal fluctuations which trigger conventional phase transitions, quantum phase transitions are driven by the zero point quantum fluctuations associated with Heisenberg's uncertainty principle.
Technetium hexafluoride or technetium(VI) fluoride (TcF6) is a yellow inorganic compound with a low melting point. It was first identified in 1961. In this compound, technetium has an oxidation state of +6, the highest oxidation state found in the technetium halides. In this respect, technetium differs from rhenium, which forms a heptafluoride, ReF7. Technetium hexafluoride occurs as an impurity in uranium hexafluoride, as technetium is a fission product of uranium (spontaneous fission in natural uranium, possible contamination from induced fission inside the reactor in reprocessed uranium). The fact that the boiling point of the hexafluorides of uranium and technetium are very close to each other presents a problem in using fluoride volatility in nuclear reprocessing.
In condensed matter physics, magnetic anisotropy describes how an object's magnetic properties can be different depending on direction. In the simplest case, there is no preferential direction for an object's magnetic moment. It will respond to an applied magnetic field in the same way, regardless of which direction the field is applied. This is known as magnetic isotropy. In contrast, magnetically anisotropic materials will be easier or harder to magnetize depending on which way the object is rotated.
Molecule-based magnets (MBMs) or molecular magnets are a class of materials capable of displaying ferromagnetism and other more complex magnetic phenomena. This class expands the materials properties typically associated with magnets to include low density, transparency, electrical insulation, and low-temperature fabrication, as well as combine magnetic ordering with other properties such as photoresponsiveness. Essentially all of the common magnetic phenomena associated with conventional transition-metal magnets and rare-earth magnets can be found in molecule-based magnets. Prior to 2011, MBMs were seen to exhibit "magnetic ordering with Curie temperature (Tc) exceeding room temperature".
Plutonium hexafluoride is the highest fluoride of plutonium, and is of interest for laser enrichment of plutonium, in particular for the production of pure plutonium-239 from irradiated uranium. This isotope of plutonium is needed to avoid premature ignition of low-mass nuclear weapon designs by neutrons produced by spontaneous fission of plutonium-240.
Samarium monochalcogenides are chemical compounds with the composition SmX, where Sm stands for the lanthanide element samarium and X denotes any one of three chalcogen elements, sulfur, selenium or tellurium, resulting in the compounds SmS, SmSe or SmTe. In these compounds, samarium formally exhibits oxidation state +2, whereas it usually assumes the +3 state, resulting in chalcogenides with the chemical formula Sm2X3.
Silicon monosulfide is a chemical compound of silicon and sulfur. The chemical formula is SiS. Molecular SiS has been detected at high temperature in the gas phase. The gas phase molecule has an Si-S bondlength of 192.93 pm, this compares to the normal single bond length of 216 pm, and is shorter than the Si=S bond length of around 201 pm reported in an organosilanethione. Historically a pale yellow-red amorphous solid compound has been reported. The behavior of silicon can be contrasted with germanium which forms a stable solid monosulfide.
Lithium molybdenum purple bronze is a chemical compound with formula Li
0.9Mo
6O
17, that is, a mixed oxide of molybdenum and lithium. It can be obtained as flat crystals with a purple-red color and metallic sheen.
Magnesium monohydride is a molecular gas with formula MgH that exists at high temperatures, such as the atmospheres of the Sun and stars. It was originally known as magnesium hydride, although that name is now more commonly used when referring to the similar chemical magnesium dihydride.
Chromium telluride (Cr2Te3) is an inorganic chemical compound. It is composed of the chromium(III) cation and the telluride anion. It has a shadowy gray color, and has a hexagonal crystal structure.
Nicholas Frederick Chilton is an Australian chemist and a Professor in the Department of Chemistry at the University of Manchester. His research is in the areas of magnetochemistry and computational chemistry, and includes the design of high-temperature single molecule magnets, molecular spin qubits for quantum information science, methods and tools for modelling magnetic calculations.
Caesium sesquioxide is a chemical compound with the formula Cs2O3 or more accurately Cs4O6. It is an oxide of caesium containing oxygen in different oxidation states. It consists of caesium cations Cs+, superoxide anions O−2 and peroxide anions O2−2. Caesium in this compound has an oxidation state of +1, while oxygen in superoxide has an oxidation state of −1/2 and oxygen in peroxide has an oxidation state of −1. This compound has a structural formula of (Cs+)4(O−2)2(O2−2). Compared to the other caesium oxides, this phase is less well studied, but has been long present in the literature. It can be created by thermal decomposition of caesium superoxide at 290 °C.