We investigate the angular distribution of positrons in the coherent process electronpositron pair creation process by high-energy photons in a periodically deformed single crystal with a complex base. The formula for the corresponding differential cross-section is derived for an arbitrary deformation field. The case is considered in detail when the photon enters into the crystal at small angles with respect to a crystallographic axis. The results of the numerical calculations are presented for${mathrm{SiO}}_{2}$ and diamond single crystals and Moliere parameterization of the screened atomic potentials in the case of the deformation field generated by the acoustic wave of S-type.
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