Of the title compounds 24 have been prepared and their lattice constants are reported. They are isotypic with the tetragonal structures variously designated as HfCuSi2-, CaMnBi2- and ZrCuSiAs-type (P4/nmm, Z = 2). Structure refinements from single-crystal X-ray data indicated considerable defects for the Mn and Cd positions in LaMn0.721(1)Sb-2 (a = 438.1(1) pm, c = 1077.2(6) pm, R = 0.024 for 314 structure factors and 16 variables), CeMn0.741(8)Sb-2 (a = 435.14(9) pm, c = 1069.0(4) pm, R = 0.022 for 233 F values and 13 variables) and LaCd0.7000(5)Sb-2 (a = 439.90(3) pm, c = 1099.7(1) pm, R = 0.044 for 488 structure factors and 13 variables), while the Au positions in LaAuSb2 (a = 443.6(1) pm, c = 1043.2(5) pm, R = 0.016 for 155 F values and 12 variables) are fully occupied.