| Identifiers | |
|---|---|
3D model (JSmol) | |
| ECHA InfoCard | 100.031.926 |
| EC Number |
|
| |
| |
| Properties | |
| ThC2 | |
| Related compounds | |
Other anions | Thorium disilicide |
Other cations | Uranium dicarbide |
Related compounds | Thorium carbide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Thorium dicarbide is an inorganic compound with the chemical formula ThC2.
Thorium dicarbide can be produced by reacting metal thorium and graphite at 2000~2500 °C: [1]
Thorium dicarbide is a yellow crystalline solid that decomposes in water. [2] It ignites at 2773 °C and becomes superconducting at 9 K. [3] At room temperature it has a monoclinic crystal structure with the space group C2/c (space group no. 15). At temperatures between 1430 °C and 1480 °C it exists in a tetragonal phase and above that in a cubic crystal structure. [4]
Thorium dicarbide can be rapidly hydrolyzed in the air to generate thorium dioxide, hydrogen and hydrocarbons. [5] Its reaction rate is 10 times that of the corresponding uranium dicarbide. [6] It can also react with acids, such as sulfuric acid, to generate thorium(IV) sulfate. [7]
The actinide or actinoid series encompasses at least the 14 metallic chemical elements in the 5f series, with atomic numbers from 89 to 102, actinium through nobelium. The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide.
Protactinium is a chemical element; it has symbol Pa and atomic number 91. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor, and inorganic acids. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.
Thorium is a chemical element. It has the symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive gray when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.
Zirconium dioxide, sometimes known as zirconia, is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabilized cubic structured zirconia, cubic zirconia, is synthesized in various colours for use as a gemstone and a diamond simulant.
Thorium dioxide (ThO2), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in colour. Also known as thoria, it is mainly a by-product of lanthanide and uranium production. Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon) and a few compounds (including tantalum carbide) have higher melting points. All thorium compounds, including the dioxide, are radioactive because there are no stable isotopes of thorium.
Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid that transitions to white with decreasing crystal size. Its structure is analogous to that of sodium chloride, but it is much less soluble in water. It is mainly used as a component of molten salts. Partly because Li and F are both light elements, and partly because F2 is highly reactive, formation of LiF from the elements releases one of the highest energies per mass of reactants, second only to that of BeO.
Uranyl chloride refers to inorganic compounds with the formula UO2Cl2(H2O)n where n = 0, 1, or 3. These are yellow-colored salts.
Lanthanum carbide (LaC2) is a chemical compound. It is being studied in relation to the manufacture of certain types of superconductors and nanotubes.
Huttonite is a thorium nesosilicate mineral with the chemical formula ThSiO4 and which crystallizes in the monoclinic system. It is dimorphous with tetragonal thorite, and isostructual with monazite. An uncommon mineral, huttonite forms transparent or translucent cream–colored crystals. It was first identified in samples of beach sands from the West Coast region of New Zealand by the mineralogist Colin Osborne Hutton (1910–1971). Owing to its rarity, huttonite is not an industrially useful mineral.
Boron can be prepared in several crystalline and amorphous forms. Well known crystalline forms are α-rhombohedral (α-R), β-rhombohedral (β-R), and β-tetragonal (β-T). In special circumstances, boron can also be synthesized in the form of its α-tetragonal (α-T) and γ-orthorhombic (γ) allotropes. Two amorphous forms, one a finely divided powder and the other a glassy solid, are also known. Although at least 14 more allotropes have been reported, these other forms are based on tenuous evidence or have not been experimentally confirmed, or are thought to represent mixed allotropes, or boron frameworks stabilized by impurities. Whereas the β-rhombohedral phase is the most stable and the others are metastable, the transformation rate is negligible at room temperature, and thus all five phases can exist at ambient conditions. Amorphous powder boron and polycrystalline β-rhombohedral boron are the most common forms. The latter allotrope is a very hard grey material, about ten percent lighter than aluminium and with a melting point (2080 °C) several hundred degrees higher than that of steel.
Uranium pentachloride is an inorganic chemical compound composed of uranium in the +5 oxidation state and five chlorine atoms.
Uranium triiodide is an inorganic compound with the chemical formula UI3. It is a black solid that is soluble in water.
Uranium(IV) iodide, also known as uranium tetraiodide, is an inorganic chemical compound. It is a salt of uranium in oxidation state +4 and iodine.
Cerium nitrate refers to a family of nitrates of cerium in the +3 or +4 oxidation state. Often these compounds contain water, hydroxide, or hydronium ions in addition to cerium and nitrate. Double nitrates of cerium also exist.
Many compounds of thorium are known: this is because thorium and uranium are the most stable and accessible actinides and are the only actinides that can be studied safely and legally in bulk in a normal laboratory. As such, they have the best-known chemistry of the actinides, along with that of plutonium, as the self-heating and radiation from them is not enough to cause radiolysis of chemical bonds as it is for the other actinides. While the later actinides from americium onwards are predominantly trivalent and behave more similarly to the corresponding lanthanides, as one would expect from periodic trends, the early actinides up to plutonium have relativistically destabilised and hence delocalised 5f and 6d electrons that participate in chemistry in a similar way to the early transition metals of group 3 through 8: thus, all their valence electrons can participate in chemical reactions, although this is not common for neptunium and plutonium.
Thorium(IV) nitrate is a chemical compound, a salt of thorium and nitric acid with the formula Th(NO3)4. A white solid in its anhydrous form, it can form tetra- and pentahydrates. As a salt of thorium it is weakly radioactive.
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.
Silicide carbides or carbide silicides are compounds containing anions composed of silicide (Si4−) and carbide (C4−) or clusters therof. They can be considered as mixed anion compounds or intermetallic compounds, as silicon could be considered as a semimetal.
Carbide chlorides are mixed anion compounds containing chloride anions and anions consisting entirely of carbon. In these compounds there is no bond between chlorine and carbon. But there is a bond between a metal and carbon. Many of these compounds are cluster compounds, in which metal atoms encase a carbon core, with chlorine atoms surrounding the cluster. The chlorine may be shared between clusters to form polymers or layers. Most carbide chloride compounds contain rare earth elements. Some are known from group 4 elements. The hexatungsten carbon cluster can be oxidised and reduced, and so have different numbers of chlorine atoms included.
Protactinium compounds are compounds containing the element protactinium. These compounds usually have protactinium in the +5 oxidation state, although these compounds can also exist in the +2, +3 and +4 oxidation states.
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