In the compounds MgCu₂O₃ and CaCu₂O₃ the Cu and O atoms are connected topologically in the same way as in the fascinating spin-ladder compound SrCu₂O₃. In contrast to the latter, the Cu-O-Cu bonding angle corresponding to the "rungs" is significantly less than 180° in MgCu₂O₃ and CaCu₂O₃. As a consequence, the magnetic susceptibility is quite different compared with that of SrCu₂O₃. Single-phase samples of CaCu₂O₃ revealed a deficiency of Ca, a balancing excess in Cu, and an oxygen deficiency corresponding to Ca_1-xCu_2+xO_3-δ. The excess Cu atoms, which are located near the Ca sites, are in the 3d¹⁰ state. The deficiency of oxygen causes a Curie term in the magnetic susceptibility due to the interruption of Cu-O-Cu bonds. From the overall behavior of the susceptibility an antiferromagnetic or dering at a Néel temperature of about 27 K is concluded.