Technetium trichloride is an inorganic compound of technetium and chlorine with the formula TcCl3.
Preparation and properties
Two polymorphs of technetium trichloride are known. The α-polymorph is prepared as a black solid from ditechnetium(III) tetraacetate dichloride and hydrogen chloride at 300 °C. It has a bioctahedral structure, consisting of triangular Tc3Cl9 units with C3v symmetry, with each Tc atom coordinated to two Tc neighbors and five chloride ligands (Tc-Tc bond length 2.44 angstrom). The Tc-Tc distances are indicative of double bonded Tc atoms. Tc3Cl9 is isostructural to its rhenium homologue, trirhenium nonachloride.1
β-TcCl3 is obtained by the reaction between technetium metal and chlorine gas. Its structure consists of infinite layers of edge-sharing octahedra, similar to MoCl3 and ReCl3, with distances that also indicate metal-metal bonding. It is less stable than α-TcCl3 and slowly transforms into it.2
References
Poineau, Frederic; Johnstone, Erik V.; Weck, Philippe F.; Kim, Eunja; Forster, Paul M.; Scott, Brian L.; Sattelberger, Alfred P.; Czerwinski, Kenneth R. (2010). "Synthesis and Structure of Technetium Trichloride". Journal of the American Chemical Society. 132 (45): 15864–5. doi:10.1021/ar400225b. PMID 24393028. /wiki/Doi_(identifier) ↩
Poineau, Frederic; Johnstone, Erik V.; Weck, Philippe F.; Kim, Eunja; Forster, Paul M.; Scott, Brian L.; Sattelberger, Alfred P.; Czerwinski, Kenneth R. (2010). "Synthesis and Structure of Technetium Trichloride". Journal of the American Chemical Society. 132 (45): 15864–5. doi:10.1021/ar400225b. PMID 24393028. /wiki/Doi_(identifier) ↩