  The electric density profile along the normal to the phase interface between
aromatic hydrocarbon toluene and water has been studied by X-ray reflectometry
using synchrotron radiation. According to the experimental data, the width of
the interface under normal conditions is (5.7 +/- 0.2) Angstrom. This value is
much larger than a theoretical value of (3.9 +/- 0.1) Angstrom predicted by the
theory of capillary waves with an interphase tension of (36.0 +/- 0.1) mN/m.
The observed broadening of the interface is attributed to its own diffuse
near-surface structure with a width no less than 4 Angstroms, which is about
the value previously discussed for high-molecular-weight n-alkane - water and
1,2-dichloroethane - water interfaces.
