Electron density study of 2H-chromene-2-thione.

The charge-density distribution in 2H-chromene-2-thione (2-thiocoumarin), C(9)H(6)OS, has been determined from X-ray diffraction data measured at 90 K using a CCD detector, to a resolution of sintheta/lambda < 1.08 A(-1). A multipolar-atom density model was fitted against 6908 reflections with I > 2sigma(I) [R(F) = 0.021, wR(F) = 0.022, goodness of fit = 1.81] in order to generate the difference Fourier maps. The topological properties of the molecular electron density in terms of the bond critical points and the evaluation of the dipole moment show that the molecular dipole moment in the crystal is higher than the corresponding value derived from theoretical calculations.