[en] The effect of point defects on the distortion character of the crystal lattice in high-purity Mo single crystals is studied. The diffuse scattering intensity is measured at T = 150 K near to the reflection 330 in the directions [110], [1-10], and [001]. The elements of the double force tensor and their tetragonality of (A-B)/(A + 2B) = 0.26 are calculated. The distortions are weak because they are due to point defects. The concentration of the impurity atoms determined by X-ray measurement is compared with those estimated from the residual resistivity ratio (RRR) and from the spectroscopic analysis. The good agreement suggests that the impurities in the Mo crystals investigated give rise to dilatation-type distortions. (author)