  The quaternary antimonide oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb)
and REZnSbO (RE = La, Ce, Pr) were synthesized from the RESb monoantimonides
and MnO, respectively ZnO. We report on single crystal X-ray data and a
detailed 121Sb M\"ossbauer spectroscopic investigation.
