The magnesium- and cadmium-rich intermetallic phases Eu T Mg 2 ( T = Rh, Pd, Ag, Ir, Pt, Au), Eu T Cd 2 ( T = Pd, Pt, Au) and CaRhMg 2 were synthesized from the elements in sealed niobium or tantalum ampoules and with heat treatments in muffle or induction furnaces. The samples were characterized by powder X-ray diffraction and the structures were refined from single crystal X-ray diffractometer data. Eu T Mg 2 ( T = Pd, Ag, Pt, Au) and Eu T Cd 2 ( T = Pd, Pt, Au) crystallize with the MgCuAl 2 type, space group Cmcm , while EuRhMg 2 , EuIrMg 2 and CaRhMg 2 adopt the YSiPd 2 type, space group Pnma . The striking crystal chemical motif of both series of compounds are networks of puckered Mg(Cd) hexagons in ABAB stacking sequence that derive from the aristotype AlB 2 ; however, with different tiling. Temperature dependent magnetic susceptibility and 151 Eu Mössbauer spectroscopic measurements indicate stable divalent europium. Antiferromagnetic ordering sets in at 20.2 (EuIrMg 2 ), 22.3 (EuPdMg 2 ), 21.3 (EuAgMg 2 ), 10.9 (EuPdCd 2 ) and 15.5 K (EuPtCd 2 ), respectively. The stable antiferromagnetic ground states are substantiated by metamagnetic transitions. The 151 Eu isomer shifts show a linear correlation with the valence electron count for the whole series of Eu T Mg 2 , Eu T Cd 2 , Eu T In 2 and Eu T Sn 2 phases.