A method for calculating the Debye temperature of a single-component substance in the amorphous state is proposed based on a nonlinear dependence of first coordination number kn of the given structure on its packing factor kp as established previously. Proceeding from previously defined parameters of the Mie–Lennard-Jones potential, the Debye temperatures have been calculated for some pure crystalline and amorphous metals, diamond, silicon, and germanium, which are in good agreement with estimations reported by other researchers. It is shown that a minimum specific Helmholtz free energy is attained at kp = 0.45556, which means that this packing corresponds to a thermodynamically stable amorphous structure.