A dry glass fibre Soxhlet thimble was charged with anhydrous iron(II) chloride (5.0 g, 39.4 mmol) inside an inert gas glove box and fitted to the Soxhlet extractor. The upper and lower joints were sealed with cones, caps or Suba Seals as appropriate. Outside the box a round-bottomed, side-arm Schlenk flask filled with anhydrous THF (200 cm³) and an efficient condenser with gas bubbler were fitted. The apparatus was purged thoroughly with argon (or dinitrogen) and the solvent was heated so as to effect gentle extraction for 4 d. By this time all the metal chloride had been extracted. The compound had already begun to separate as a white microcrystalline solid. The solution was left to cool to ambient temperature and concentrated to ca. 50cm³ before the solid was collected by cannula filtration and dried in vacuo for 3 h. (8.5 g, 92 %).

Anal. Found (Calcd. For C₁₂H₂₄Cl₄Fe₂O₃): C 30.58 (30.68); H 5.16 (5.15) %.