Crystal structure of methyl chloro-formate

The crystal structure of methyl chloro-formate, C₂H₃ClO₂, was determined by single-crystal X-ray diffraction data at 200 and 100 K. A suitable single crystal was grown in a capillary directly on the goniometer via Ostwald ripening around its melting point at 210 K. The ClC(O)OCH₃ mol-ecule has a staggered conformation and is planar (without H atoms) with point group C _S. In the crystal, methyl chloro-formate features weak Cl⋯O inter-actions forming chains along [100], which again extend into a network via inter-molecular C⋯O dipole inter-actions, consistent with Hirshfeld surface analysis. Complementary quantum chemical calculations at the DFT-def2-TZVP/PBE0-D3 level of theory were performed to compare with the experimental Raman data in both the liquid and solid state.