Rhodium trichloride, also known as rhodium chloride, is a kind of red-brown powder, easy to deliquescence. Used in electronics, instrumentation, metallurgy and other industries, also used in electroplating operations, catalyst preparation.Rhodium trichloride trihydrate is a kind of Lewis acid, which can form various complexes with ligands. Unlike Rh (I), the RH (III) complexes are mostly octahedral, which are relatively stable in kinetics.
Under mild conditions,Rhodium trichloride reacts with tertiary phosphine to form RhCl3 (PR3) 3 type complexes. If the reaction is carried out in boiling ethanol solution, rhodium is reduced to form Rh (I) complex, such as Wilkinson's catalyst - RhCl (PPh3) 3. The reductant in the reaction is ethanol or triphenylphosphine, and the corresponding oxidation products are acetaldehyde and triphenylphosphine oxide.
When boiled with ethanol and pyridine, Rhodium trichloride is converted to trans-[RhCl2(py)4)]Cl. If the solvent is water, a surface-RhCl3 (py) 3 with a structure similar to that of thioether complexes is obtained. Blue paramagnetic [Cl(py)4Rh-O2 Rh(py)4Cl]5+ was obtained by oxidation of trans-[RhCl2(py)4)]Cl.
Ammonia reacts with ethanol solution of rhodium trichloride to form pentaammonia chloride ion [RhCl(NH3)5]2+. A colorless hydrogen complex [RhH (NH3) 5] SO4 was obtained after the ion was reduced by zinc and salted by sulfate.Rhodium trichloride trihydrate can also coordinate with olefins, especially those of norbornadiene and 1,5-cyclooctadiene, in the form of Rh2Cl2 (olefin) 4. Its coordination with 1,5-cyclooctadiene is particularly stable. Even when it reacts with 1,3-cyclooctadiene in ethanol, 1,5-cyclooctadiene can be obtained. Diene ligands can be removed by cyanide ions.