Rhenium trichloride
Encyclopedia
Rhenium trichloride is a compound
of rhenium
and chlorine
. It was first discovered in 1932 by Geilnann, Wriuce, and Biltz.
of rhenium trichloride consists of well-defined Re3Cl9 units that are connected by chlorine atom bridges. The Re3Cl9 unit structure also applies to rhenium trichloride dissolved in a variety of solvents, with the only possible exception being the dimer structure when dissolved in acetic acid. The Re3Cl9 crystal structure has C3v symmetry.
Rhenium trichloride is comparatively non-volatile but produces a green vapour during strong heating. It may have a very small temperature-independent paramagnetism
, but the susceptibility is ambiguous.
tests show no observable difference in structure between the untreated and vacuum sublimed material.
The heat of oxidation
according to the equation,
is 190.7 ± 0.2 kcal/mol.
, the thermal decomposition of salts of hexachlororhenic(IV) acid, or the heating of Re2(O2CCH3)4Cl2 under HCl gas.
-metal complexes that act as electron reservoirs.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
of rhenium
Rhenium
Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion , rhenium is one of the rarest elements in the Earth's crust. The free element has...
and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
. It was first discovered in 1932 by Geilnann, Wriuce, and Biltz.
Structure and physical properties
The crystal structureCrystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
of rhenium trichloride consists of well-defined Re3Cl9 units that are connected by chlorine atom bridges. The Re3Cl9 unit structure also applies to rhenium trichloride dissolved in a variety of solvents, with the only possible exception being the dimer structure when dissolved in acetic acid. The Re3Cl9 crystal structure has C3v symmetry.
Rhenium trichloride is comparatively non-volatile but produces a green vapour during strong heating. It may have a very small temperature-independent paramagnetism
Paramagnetism
Paramagnetism is a form of magnetism whereby the paramagnetic material is only attracted when in the presence of an externally applied magnetic field. In contrast with this, diamagnetic materials are repulsive when placed in a magnetic field...
, but the susceptibility is ambiguous.
Chemical properties
Rhenium trichloride prepared from rhenium pentachloride without further treatment is chemically reactive, but if it is vacuum sublimed at 500oC, then it becomes comparatively unreactive. However, x-ray diffractionX-ray crystallography
X-ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and causes the beam of light to spread into many specific directions. From the angles and intensities of these diffracted beams, a crystallographer can produce a...
tests show no observable difference in structure between the untreated and vacuum sublimed material.
The heat of oxidation
Standard enthalpy change of reaction
The standard enthalpy of reaction is the enthalpy change that occurs in a system when one mole of matter is transformed by a chemical reaction under standard conditions.For a generic chemical reaction...
according to the equation,
- ReCl3(s) + 4OH- + 2OCl- → ReO4- + 2H2O + 5Cl-
is 190.7 ± 0.2 kcal/mol.
Preparation
Rhenium trichloride is most efficiently prepared by the thermal decomposition of rhenium pentachloride in nitrogen. Other methods include reacting sulphuryl chloride with rhenium powder with or without the addition of aluminium chlorideAluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
, the thermal decomposition of salts of hexachlororhenic(IV) acid, or the heating of Re2(O2CCH3)4Cl2 under HCl gas.
Uses
Rhenium trichloride is used as a starting material for synthesis of rhenium complexes. ReCl3 can react with peralkylated benzeneBenzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
-metal complexes that act as electron reservoirs.