Tetra-kis(µ-2-phen-oxy-propionato)-κO,O':O';κO:O,O';κO:O'-bis-[(1,10-phenanthroline-κN,N')(2-phen-oxy-propionato-κO,O')holmium(III)].

The title compound, [Ho(2)(C(9)H(9)O(3))(6)(C(12)H(8)N(2))(2)], lies about a centre of symmetry and is comprised of six 2-phen-oxy-propionate (POPA) anions and two 1,10-phenanthroline (phen) ligands. The two Ho(III) ions are linked by four POPA groups utilizing both bi- and tridentate bridging modes to form an inversion-symmetric dimer. Each Ho(III) ion is nine-coordinate, with a chelating 1,10-phenanthroline mol-ecule, one bidentate chelating carboxyl-ate group, two bidentate bridging carboxyl-ate groups and two tridentate bridging carboxyl-ate groups in a distorted mono-capped square anti-prism geometry. There are weak π-π aromatic inter-actions between the phen groups and aromatic rings of the POPA ligands [centroid-centroid distance = 3.829 (1) Å].