Crystal structure of methyl chloroformate

The crystal structure of methyl chloroformate, C 2 H 3 ClO 2 , 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)OCH 3 molecule has a staggered conformation and is planar (without H atoms) with point group C S . In the crystal, methyl chloroformate features weak Cl...O interactions forming chains along [100], which again extend into a network via intermolecular C...O dipole interactions, 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.