Diethylcadmium (Cd(C₂H₅)₂)

Loading

  • Diethylcadmium is an organometallic compound with the formula Cd(C₂H₅)₂, composed of a cadmium atom covalently bonded to two ethyl groups. 
  • It is a colorless to faintly yellow, highly toxic liquid with a density of about 1.9–2.1 g/cm³ and a boiling point in the range of 150–160 °C under atmospheric pressure. 
  • Like other cadmium alkyls, it is extremely sensitive to air and moisture, reacting violently with water to produce ethane and cadmium hydroxide. 
  • Although it is less volatile than dimethylcadmium due to the larger ethyl substituents, it still presents a significant inhalation hazard and requires rigorous inert-atmosphere handling.
  • Structurally, diethylcadmium features a roughly linear geometry around the cadmium center in the gas phase, with two σ-bonded ethyl groups oriented opposite each other. In solution or solid-state complexes, the coordination environment can be influenced by interactions with solvents or additional ligands, producing slight deviations from idealized linearity. The Cd–C bonds are covalent but polar, with cadmium carrying partial positive charge due to its lower electronegativity relative to carbon. These bonds are somewhat weaker than in analogous zinc alkyls, which contributes to its comparatively higher reactivity and lower thermal stability.
  • Chemically, diethylcadmium functions as an ethylating agent, capable of transferring ethyl groups to various electrophilic substrates. It reacts with acyl halides to yield ketones, with aldehydes to form secondary alcohols after hydrolysis, and with certain metal halides to produce ethyl-substituted organometallic species. Compared with Grignard reagents or organolithium compounds, diethylcadmium is milder and more selective, making it useful in synthesis when sensitive functional groups must be preserved. In materials science, it has served as a precursor in vapor-phase deposition techniques, such as metal–organic chemical vapor deposition (MOCVD), for producing cadmium-containing thin films, though it is used far less frequently than dimethylcadmium due to its lower volatility and similar toxicity.
  • Synthesis of diethylcadmium is typically accomplished by the reaction of cadmium halides (often CdCl₂) with ethylmagnesium bromide or ethyl lithium under strictly anhydrous, oxygen-free conditions. The product is purified by distillation under reduced pressure, and all manipulations are carried out in sealed, inert systems such as Schlenk lines or glove boxes.
  • Toxicologically, diethylcadmium is extremely hazardous, combining the systemic poisoning effects of cadmium with the inherent dangers of volatile organometallic liquids. Acute exposure can cause severe respiratory injury, kidney damage, and liver toxicity, while chronic exposure is associated with carcinogenesis and irreversible organ damage. Because its vapor pressure is lower than dimethylcadmium, it poses slightly less risk of accidental airborne exposure, but the hazard remains severe. 
  • Modern use is rare, limited to specialized research settings where its reactivity is uniquely valuable and no suitable safer alternative exists. Disposal involves controlled oxidation to fully degrade both the organic groups and the cadmium content before final waste processing.
Author: admin

Leave a Reply

Your email address will not be published. Required fields are marked *