The Mössbauer spectra of the compounds Cu2CdSn(S1−xSex)4 and Cu2CdSn(Se1−xTex)4 (x = 0; 0.25; 0.5; 0.75, and 1) are investigated. The linear increase of the Mössbauer isomer shift with the increase of x is observed. Comparison with the isomer shift for Cu2Sn(S1−xSex)3 and for AgCrSn(S1−xSex)4 reveals the existence two correlations between the Mössbauer isomer shift and the interatomic distance. The isomer shift as well as the interatomic distance increase while replacing S atoms by Se atoms (or Se atoms by Te atoms) in the nearest enivironment of the Mössbauer nucleus. The isomer shift strongly decreases with the increase of the interatomic distance for the compounds, which belong to different systems, but with the same x (with the same nearest environment of tin atoms).