Ruthenium trichloride

Ruthenium(III) chloride

Identifiers
CAS Number	10049-08-8 Y 13815-94-6 (trihydrate) Y 14898-67-0 (x-hydrate) Y
3D model (Jmol)	Interactive image
ChemSpider	74294 Y
ECHA InfoCard	100.030.139
PubChem CID	82323
RTECS number	VM2650000
UNII	RY8V1UJV23 N
InChI InChI=1S/3ClH.Ru/h3*1H;/q;;;+3/p-3 Y Key: YBCAZPLXEGKKFM-UHFFFAOYSA-K Y InChI=1/3ClH.Ru/h3*1H;/q;;;+3/p-3 Key: YBCAZPLXEGKKFM-DFZHHIFOAX
SMILES [Cl-].[Cl-].[Cl-].[Ru+3]
Properties
Chemical formula	RuCl3·xH2O
Molar mass	207.43 g/mol
Melting point	> 500 °C (932 °F; 773 K) (decomposes)
Solubility in water	Soluble
Magnetic susceptibility (χ)	+1998.0·10−6 cm3/mol
Structure
Crystal structure	trigonal (RuCl3), hP8
Space group	P3c1, No. 158
Coordination geometry	octahedral
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Ruthenium(III) bromide
Other cations	Rhodium(III) chloride Iron(III) chloride
Related compounds	Ruthenium tetroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Ruthenium(III) chloride is the chemical compound with the formula RuCl₃. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl₃·xH₂O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry.

Anhydrous ruthenium(III) chloride is usually prepared by heating powdered ruthenium metal with chlorine. In the original synthesis, the chlorination was conducted in the presence of carbon monoxide, the product being carried by the gas stream and crystallising upon cooling. Two allotropes of RuCl₃ are known. The black α-form adopts the CrCl₃-type structure with long Ru-Ru contacts of 346 pm. The dark brown metastable β-form crystallizes in a hexagonal cell; this form consists of infinite chains of face-sharing octahedra with Ru-Ru contacts of 283 pm, similar to the structure of zirconium trichloride. The β-form is irreversibly converted to the α-form at 450–600 °C. The β-form is diamagnetic, whereas α-RuCl₃ is paramagnetic.

RuCl₃ vapour decomposes into the elements at high temperatures ; the enthalpy change at 750 °C (1020 K), Δ_dissH₁₀₂₀ has been estimated as +240 kJ/mol.

As the most commonly available ruthenium compound, RuCl₃·xH₂O is the precursor to many hundreds of chemical compounds. The noteworthy property of ruthenium complexes, chlorides and otherwise, is the existence of more than one oxidation state, several of which are kinetically inert. All second and third-row transition metals form exclusively low spin complexes, whereas ruthenium is special in the stability of adjacent oxidation states, especially Ru(II), Ru(III) (as in the parent RuCl₃·xH₂O) and Ru(IV).

The benzene ligand can be exchanged with other arenes such as hexamethylbenzene.

This reaction proceeds via the intermediate cis-Ru(bipy)₂Cl₂.