Synthesis and structure of technetium trichloride

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Materials Science

Background:

• Technetium chemistry is less explored than its lighter homologues.
• Understanding the synthesis and structure of technetium halides is crucial for advancing inorganic chemistry.
• Previous studies on rhenium halide formation provide a basis for comparison.

Purpose of the Study:

• To synthesize technetium trichloride (TcCl3).
• To elucidate the reaction mechanism for TcCl3 formation.
• To characterize the crystal structure of TcCl3 and compare it with rhenium analogues.

Main Methods:

• Synthesis of TcCl3 through the reaction of Tc2(O2CCH3)4Cl2 with gaseous HCl at elevated temperatures (300 °C).
• Identification of an intermediate compound, Tc2(O2CCH3)2Cl4, formed at lower temperatures (100 °C).
• X-ray crystallography was used to determine the crystal structure of TcCl3, revealing Tc3Cl9 clusters.

Main Results:

• Technetium trichloride (TcCl3) was successfully synthesized.
• An intermediate, Tc2(O2CCH3)2Cl4, was identified during the synthesis process.
• TcCl3 was found to be isostructural with rhenium trichloride, featuring Tc3Cl9 clusters with a Tc-Tc separation of 2.444(1) Å.

Conclusions:

• The synthesis of technetium trichloride is achieved through a reaction mimicking rhenium halide formation.
• The crystal structure of TcCl3 consists of Tc3Cl9 clusters, similar to its rhenium counterpart.
• Computational studies support the stability of TcCl3 and suggest potential polymorphs for TcBr3.