The crystal structure of formic acid

The crystal structure of formic acid has been determined at --504-5 ° C., using single-crystal X-ray diffraction techniques.The unit cell is orthorhombic with a = 10.23±0-02,b = 3-64±0.01,and c = 5.34±0.01/~.There are four molecules per unit cell.The space group is Pna.Bond lengths have been determined using Fourier projections on ( 010) and ( 001).The C-O bond length is 1.26±0.03,C=O 1.23:t:0.03/~ and the O-C=O angle 123±1 °.The molecules are arranged in the form of infinite chains in the crystal, each molecule being linked to two neighbors by hydrogen bonds.The length of the hydrogen (O-H... O) bond is 2.58±0.03/~.