Molecular structure of crystalline complex SbCl₅ • Py was determined for the first time and the structure of the complex SbCl₅ • AN was refined by means of single crystal X-ray diffraction analysis. It is shown that donor-acceptor Sb–N bond lengths for these complexes are equal within the experimental error. Quantum chemical calculations of the complexes in the gas phase reveal that the energies of the donor-acceptor bond Sb–N are 88 and 180 kJ mol⁻¹ for SbCl₅ • AN and SbCl₅ • Py, respectively. It is established that the length of the donor-acceptor bond Sb–N in the crystal cannot serve as a measure of its strength.