[en] The local defect structures of deuterium as well as of nitrogen-deuterium pairs in niobium were investigated. This was done with the method of the coherent quasi-elastic, diffuse scattering of thermal neutrons in great distance to high Miller indices of Bragg reflections (intermediate reflex scattering), which was experimentally determined at NbD_0.0170 monocrystals, NbN_0.0143 monocrystals and NbN_0.0143D_0.0110 monocrystals. The influences of the lattice distortions in close vicinity to the defect can be proved for high scattering vectors in low-symmetrical directions. For the NbN_0.0143 system, it was demonstrated that the static lattice distortions lead to a characteristic attenuation of the host lattice phonons. This loss of intensity (static Debye-Waller factor) was quantitatively determined for selected TA-phonons. It is shown that the combination of these measuring results with the results from the diffuse neutron scattering can supply valuable information about the defect structure. (orig./MM)