Complexes of alkaline earth metal ions with the oxygen-containing ligand 1,3-bis(2-hydroxyphenyl)- 1,3-propanedione (bhppH3) have been synthesized. Conductivity, spectral and thermal measurements indicate a non ionic behaviour for all these complexes. IR spectral data suggest a difference in coordination mode between Mg and the other metals. A molecular structure similar to that found in Zn(bhppH2)2sigma; 2EtOH is proposed for the Mg complex. © 1986.