Names | |||
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Preferred IUPAC name Tetrabromomethane [1] | |||
Other names
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Identifiers | |||
3D model (JSmol) | |||
Abbreviations | R-10B4[ citation needed ] | ||
1732799 | |||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.008.355 | ||
EC Number |
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26450 | |||
MeSH | carbon+tetrabromide | ||
PubChem CID | |||
RTECS number |
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UNII | |||
UN number | 2516 | ||
CompTox Dashboard (EPA) | |||
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Properties | |||
CBr4 | |||
Molar mass | 331.627 g·mol−1 | ||
Appearance | Colorless to yellow-brown crystals | ||
Odor | sweet odor | ||
Density | 3.42 g mL−1 | ||
Melting point | 94.5 °C; 202.0 °F; 367.6 K | ||
Boiling point | 189.7 °C; 373.4 °F; 462.8 K decomposes | ||
0.024 g/100 mL (30 °C) | |||
Solubility | soluble in ether, chloroform, ethanol | ||
Vapor pressure | 5.33 kPa (at 96.3 °C) | ||
−93.73·10−6 cm3/mol | |||
Refractive index (nD) | 1.5942 (100 °C) | ||
Structure | |||
Monoclinic | |||
Tetragonal | |||
Tetrahedron | |||
0 D | |||
Thermochemistry | |||
Heat capacity (C) | 0.4399 J K−1 g−1 | ||
Std molar entropy (S⦵298) | 212.5 J/mol K | ||
Std enthalpy of formation (ΔfH⦵298) | 26.0–32.8 kJ mol−1 | ||
Gibbs free energy (ΔfG⦵) | 47.7 kJ/mol | ||
Std enthalpy of combustion (ΔcH⦵298) | −426.2–−419.6 kJ mol−1 | ||
Hazards | |||
GHS labelling: | |||
Danger | |||
H302, H315, H318, H335 | |||
P261, P280, P305+P351+P338 | |||
NFPA 704 (fire diamond) | |||
Flash point | noncombustible [3] | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
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NIOSH (US health exposure limits): | |||
PEL (Permissible) | none [3] | ||
REL (Recommended) | TWA 0.1 ppm (1.4 mg/m3) ST 0.3 ppm (4 mg/m3) [3] | ||
IDLH (Immediate danger) | N.D. [3] | ||
Safety data sheet (SDS) | inchem.org | ||
Related compounds | |||
Other anions | Carbon tetrafluoride Carbon tetrachloride Carbon tetraiodide | ||
Other cations | Silicon tetrabromide Germanium tetrabromide Tin(IV) bromide | ||
Related alkanes | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Carbon tetrabromide, CBr4, also known as tetrabromomethane, is a bromide of carbon. Both names are acceptable under IUPAC nomenclature.
CBr4 can be obtained by the bromination of methane. The byproducts include other brominated methanes (methyl bromide, dibromomethane and bromoform) and hydrogen bromide. This process is analogous to the chlorination of methane:
Halogen exchange of carbon tetrachloride with aluminium bromide gives higher yields with aluminium chloride as the byproduct: [4]
Tetrabromomethane has two polymorphs: crystalline II or β below 46.9 °C (320.0 K) and crystalline I or α above 46.9 °C. Monoclinic polymorph has space group C2/c with lattice constants: a = 20.9, b = 12.1, c = 21.2 (.10−1 nm), β = 110.5°. [5] Bond energy of C–Br is 235 kJ.mol−1. [6]
Due to its symmetrically substituted tetrahedral structure, its dipole moment is 0 Debye. Critical temperature is 439 °C (712 K) and critical pressure is 4.26 MPa. [5]
The high temperature α phase is known as a plastic crystal phase. Roughly speaking, the CBr4 are situated on the corners of the cubic unit cell as well as on the centers of its faces in an fcc arrangement. It was thought in the past that the molecules could rotate more or less freely (a 'rotor phase'), so that on a time average they would look like spheres. Recent work [7] has shown, however, that the molecules are restricted to only 6 possible orientations (Frenkel disorder). Moreover, they cannot take these orientations entirely independently from each other because in some cases the bromine atoms of neighboring molecules would point at each other leading to impossibly short distances. This rules out certain orientational combinations when two neighbor molecules are considered. Even for the remaining combinations displacive changes occur that better accommodate neighbor to neighbor distances. The combination of censored Frenkel disorder and displacive disorder implies a considerable amount of disorder inside the crystal which leads to highly structured sheets of diffuse scattered intensity in X-ray diffraction. In fact, it is the structure in the diffuse intensity that provides the information about the details of the structure.
In combination with triphenylphosphine, CBr4 is used in the Appel reaction, which converts alcohols to alkyl bromides. Similarly, CBr4 is used in combination with triphenylphosphine in the first step of the Corey–Fuchs reaction, which converts aldehydes into terminal alkynes. It is significantly less stable than lighter tetrahalomethanes. It is made via bromination of methane using HBr or Br2. It can be also prepared by more economical reaction of tetrachloromethane with aluminium bromide at 100 °C. [6]
It is used as a solvent for greases, waxes, and oils, in plastic and rubber industry for blowing and vulcanization, further for polymerization, as a sedative and as an intermediate in manufacturing agrochemicals. Due to its non-flammability it is used as an ingredient in fire-resistant chemicals. [8]
Bromine is a chemical element; it has symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig and Antoine Jérôme Balard, its name was derived from the Ancient Greek βρῶμος (bromos) meaning "stench", referring to its sharp and pungent smell.
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula CH3Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s. From the chemistry perspective, it is one of the halomethanes.
Hydrobromic acid is an aqueous solution of hydrogen bromide. It is a strong acid formed by dissolving the diatomic molecule hydrogen bromide (HBr) in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at 124.3 °C (255.7 °F) and contains 47.6% HBr by mass, which is 8.77 mol/L. Hydrobromic acid is one of the strongest mineral acids known.
Hydrogen bromide is the inorganic compound with the formula HBr. It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temperature. Aqueous solutions that are 47.6% HBr by mass form a constant-boiling azeotrope mixture that boils at 124.3 °C (255.7 °F). Boiling less concentrated solutions releases H2O until the constant-boiling mixture composition is reached.
Phosphorus tribromide is a colourless liquid with the formula PBr3. The liquid fumes in moist air due to hydrolysis and has a penetrating odour. It is used in the laboratory for the conversion of alcohols to alkyl bromides.
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.
A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains. Although uncommon, chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms. Bromide toxicity can also cause a type of skin eruption, see potassium bromide. The bromide ion has an ionic radius of 196 pm.
Aluminium bromide is any chemical compound with the empirical formula AlBrx. Aluminium tribromide is the most common form of aluminium bromide. It is a colorless, sublimable hygroscopic solid; hence old samples tend to be hydrated, mostly as aluminium tribromide hexahydrate (AlBr3·6H2O).
Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. It is abbreviated by chemists as EtBr. This volatile compound has an ether-like odor.
Boron tribromide, BBr3, is a colorless, fuming liquid compound containing boron and bromine. Commercial samples usually are amber to red/brown, due to weak bromine contamination. It is decomposed by water and alcohols.
Arsenic tribromide is an inorganic compound with the formula AsBr3, it is a bromide of arsenic. Arsenic is a chemical element that has the symbol As and atomic number 33. This pyramidal molecule is the only known binary arsenic bromide. AsBr3 is noteworthy for its very high refractive index of approximately 2.3. It also has a very high diamagnetic susceptibility. The compound exists as colourless deliquescent crystals that fume in moist air.
Bromine compounds are compounds containing the element bromine (Br). These compounds usually form the -1, +1, +3 and +5 oxidation states. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X2/X− couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states than iodination but lower or equal oxidation states to chlorination. Bromine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Br bonds.
Copper(I) bromide is the chemical compound with the formula CuBr. This diamagnetic solid adopts a polymeric structure akin to that for zinc sulfide. The compound is widely used in the synthesis of organic compounds and as a lasing medium in copper bromide lasers.
Strontium bromide is a chemical compound with a formula SrBr2. At room temperature it is a white, odourless, crystalline powder. Strontium bromide imparts a bright red colour in a flame test, showing the presence of strontium ions. It is used in flares and also has some pharmaceutical uses.
Dibromomethane or methylene bromide, or methylene dibromide is a halomethane with the formula CH2Br2. It is slightly soluble in water but very soluble in organic solvents. It is a colorless liquid.
Bromochloromethane or methylene bromochloride and Halon 1011 is a mixed halomethane. It is a heavy low-viscosity liquid with refractive index 1.4808.
Phenacyl bromide is the organic compound with the formula C6H5C(O)CH2Br. This colourless solid is a powerful lachrymator as well as a useful precursor to other organic compounds.
Organobromine chemistry is the study of the synthesis and properties of organobromine compounds, also called organobromides, which are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane.
Carbonyl bromide, also known as bromophosgene, is an organic chemical compound with the chemical formula COBr2. It is a colorless liquid. It is a bromine analogue of phosgene. It is a carbon oxohalide. Carbonyl bromide is a decomposition product of halon compounds used in fire extinguishers.
Xylylene dibromide is an organic compound with the formula C6H4(CH2Br)2. It is an off-white solid that, like other benzyl halides, a strong lachrymator. It is a useful reagent owing to the convenient reactivity of the two C-Br bonds. Two other isomers are known, para- and meta-xylylene dibromide.