Three novel μ 3 -oxo trinuclear carboxylates [Fe 2 CaO(CCl 3 COO) 6 (THF) 4 ]·THF (1), [Fe 2 SrO(CCl 3 COO) 6 (THF) 6 ]·0.5H 2 O·0.5THF (2) and [Fe 2 BaO(CCl 3 COO) 6 (THF) 6 ]·0.5H 2 O·0.5THF (3) have been synthesised and subsequently characterised by X-ray structure analysis, thermal gravimetry (TG), infra red (IR) spectroscopy and magnetic measurements. Compounds 1 and 3 are molecular complexes with s- and d-metals displayed in the apexes of isosceles triangles with a triply bridging oxygen atom at its centre. The Ca⋯Fe and Ba⋯Fe separations have the values 3.750(1) and 4.177(1)Å, respectively. In comparison with these, Fe⋯Fe separations, 3.229(2)Å in 1 and 3.201(1)Å in 3, appear much shorter. The molecular complexes obey C 2 symmetry with the twofold axis passing through s metal and μ 3 -oxo atom. The coordination numbers are 6, 7 and 9 for iron, calcium and barium correspondingly.Magnetic studies reveal the presence of an antiferromagnetic exchange in the isosceles triangular skeletons of the trinuclear species. Using the spin Hamiltonian H=−2J 12 [S 1 S 2 ], the fitting parameters g Fe =2.00, J Fe–Fe =−58.90cm −1 for 1 and −60.40cm −1 for 3; g Fe =2.14, J Fe–Fe =−75.40cm −1 for 2 have been estimated.