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Phosphorus pentabromide is a reactive, yellow solid of formula P Br 5, which has the structure [PBr 4] + Br − (tetrabromophosphonium bromide) in the solid state but in the vapor phase is completely dissociated to PBr 3 and Br 2.
Phosphorus pentachloride, phosphorus pentabromide, and phosphorus heptabromide are ionic in the solid and liquid states; PCl 5 is formulated as PCl 4 + PCl 6 –, but in contrast, PBr 5 is formulated as PBr 4 + Br −, and PBr 7 is formulated as PBr 4 + Br 3 −. They are widely used as chlorinating and brominating agents in organic chemistry.
The following table contains the 92 Johnson solids, with edge length . The table includes the solid's enumeration (denoted as J n {\displaystyle J_{n}} ). [ 8 ] It also includes the number of vertices, edges, and faces of each solid, as well as its symmetry group , surface area A {\displaystyle A} , and volume V {\displaystyle V} .
In the solid state PCl 5 is an ionic compound called tetrachlorophosphonium hexachlorophosphate formulated PCl + 4 PCl − 6. [6] Structure of solid phosphorus pentachloride, illustrating its autoionization at higher concentrations. [7] In solutions of polar solvents, PCl 5 undergoes self-ionization. [8]
The terms first and second are in reference to crude product soluble and crude product insoluble solvents respectively. Typically, the second solvent, following the dissolution of the impure solid in the first solvent, is added slowly until the desired product begins to crystallize from solution.
[1] [2] [3] There are many forms of polymerization [4] and different systems exist to categorize them. IUPAC definition for polymerization In chemical compounds , polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants [ 3 ] and their inherent steric effects .
The solubility of a specific solute in a specific solvent is generally expressed as the concentration of a saturated solution of the two. [1] Any of the several ways of expressing concentration of solutions can be used, such as the mass, volume, or amount in moles of the solute for a specific mass, volume, or mole amount of the solvent or of the solution.
Weinreb and Nahm originally proposed the following reaction mechanism to explain the selectivity shown in reactions of the Weinreb–Nahm amide. Their suggestion was that the tetrahedral intermediate (A below) formed as a result of nucleophilic addition by the organometallic reagent is stabilized by chelation from the methoxy group as shown. [1]