| IUPAC name |
|Other names |
3D model (JSmol)
|Molar mass||415.29 g/mol|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Uranium pentachloride is an inorganic chemical compound composed of uranium in the +5 oxidation state and five chlorine atoms.
Uranium pentachloride can be prepared from the reaction of uranium trioxide with carbon tetrachloride, with a previously prepared amount of the compound serving as a catalyst.
It can also be prepared from the reaction between uranium tetrachloride and chlorine in a fluidized bed reactor at 550 °C.
Uranium pentachloride is available as red-brown microcrystalline powders or black-red crystals with metallic sheen. Unlike the tetrachloride, it is soluble in liquid chlorine. It is very hygroscopic and decomposes into uranium hexachloride and uranium tetrachloride when in water or heated. Additionally, it reacts with some organic solvents such as alcohols, acetone, diethyl ether, or dioxane, but does form stable solutions in carbon tetrachloride, carbon disulfide, and thionyl chloride.
There are two crystalline forms, each of which has the uranium atom in an octahedral geometry among six chlorine atoms. Usually, it is in the α-form, which has a monoclinic crystal structure with space group P21/n. There is also a triclinic β-form, which has space group P1 and consists of U2Cl10 dimers like in uranium pentabromide.
The gaseous form has C4v symmetry due to strong f-orbital contribution, and has an electron affinity of 4.76±0.03 eV.
Protactinium is a chemical element with the symbol Pa and atomic number 91. It is a dense, 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.
Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colourless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications.
Niobium(V) chloride, also known as niobium pentachloride, is a yellow crystalline solid. It hydrolyzes in air, and samples are often contaminated with small amounts of NbOCl3. It is often used as a precursor to other compounds of niobium. NbCl5 may be purified by sublimation.
Tantalum(V) chloride, also known as tantalum pentachloride, is an inorganic compound with the formula TaCl5. It takes the form of a white powder and is commonly used as a starting material in tantalum chemistry. It readily hydrolyzes to form tantalum(V) oxychloride (TaOCl3) and eventually tantalum pentoxide (Ta2O5); this requires that it be synthesised and manipulated under anhydrous conditions, using air-free techniques.
Uranyl chloride refers to inorganic compounds with the formula UO2Cl2(H2O)n where n = 0, 1, or 3. These are yellow-colored solids.
A uranate is a ternary oxide involving the element uranium in one of the oxidation states 4, 5 or 6. A typical chemical formula is MxUyOz, where M represents a cation. The uranium atom in uranates(VI) has two short collinear U–O bonds and either four or six more next nearest oxygen atoms. The structures are infinite lattice structures with the uranium atoms linked by bridging oxygen atoms.
Uranium tetrachloride is an inorganic compound, a salt of uranium and chlorine, with the formula UCl4. It is a hygroscopic olive-green solid. It was used in the electromagnetic isotope separation (EMIS) process of uranium enrichment. It is one of the main starting materials for organouranium chemistry.
Uranium(III) chloride, UCl3, is a water soluble salt of uranium. UCl3 is used mostly to reprocess spent nuclear fuel. Uranium(III) chloride is synthesized in various ways from uranium(IV) chloride; however, UCl3 is less stable than UCl4.
Uranium borohydride is the inorganic compound with the empirical formula U(BH4)4. Two polymeric forms are known, as well as a monomeric derivative that exists in the gas phase. Because the polymers convert to the gaseous form at mild temperatures, uranium borohydride once attracted much attention. It is solid green.
Uranium pentafluoride is the inorganic compound with the chemical formula UF5. It is a pale yellow paramagnetic solid. The compound has attracted interest because it is related to uranium hexafluoride, which is widely used to produce uranium fuel. It crystallizes in two polymorphs, called α- and β-UF5.
Organoactinide chemistry is the science exploring the properties, structure and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond.
Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2. SeCl4 is used in the synthesis of other selenium compounds.
Niobium oxychloride is the inorganic compound with the formula NbOCl3. It is a white, crystalline, diamagnetic solid. It is often found as an impurity in samples of niobium pentachloride, a common reagent in niobium chemistry.
Polonium tetrachloride (also known as polonium(IV) chloride) is a chemical compound with the formula PoCl4. The salt is a hygroscopic bright yellow crystalline solid at room temperature. Above 200 °C, it tends to decompose into polonium dichloride and excess chlorine, similar to selenium tetrachloride and tellurium tetrachloride.
Uranium pentabromide is an inorganic chemical compound with the formula UBr5.
Uranium hexachloride (UCl6) is an inorganic chemical compound of uranium in the +6 oxidation state. UCl6 is a metal halide composed of uranium and chlorine. It is a multi-luminescent dark green crystalline solid with a vapor pressure between 1-3 mmHg at 373.15 K. UCl6 is stable in a vacuum, dry air, nitrogen and helium at room temperature. It is soluble in carbon tetrachloride (CCl4). Compared to the other uranium halides, little is known about UCl6.
Titanium nitrate is the inorganic compound with formula Ti(NO3)4. It is a colorless, diamagnetic solid that sublimes readily. It is an unusual example of a volatile binary transition metal nitrate. Ill defined species called titanium nitrate are produced upon dissolution of titanium or its oxides in nitric acid.
Chlorotrifluorosilane is an inorganic gaseous compound with formula SiClF3 composed of silicon, fluorine and chlorine. It is a silane that substitutes hydrogen with fluorine and chlorine atoms.
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.
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.