We firstly report on the leading scattering mechanism responsible for the heat resistivity in simple molecular crystals. The analysis is given in the terms the phonon and libron three-particle-scattering processes in crystals formed by linear molecules (N2, CO, CO2, N2O, etc.) On the basis of a comparison of heat resistivity estimations with known experimental data the dominated microscopic scattering mechanism is established, namely, the process of absorption (and emission) of the one libron by the two acoustic phonons.
