A new barium acetate phase, di-μ₅-acetato-tri-μ₄-acetato-tri-μ₃-acetato-tri-μ₂-acetato-μ₂-acetato-triaquahemiaquahexabarium(II), of analytical formula [Ba₆(C₂H₃O₂)₁₂(H₂O)_3.5], is described. The asymmetric unit contains six independent Ba centres with coordination numbers varying from 7 to 10 arising from bonding to 12 crystallographically independent acetate ligands and four molecules of water, one of which is disordered over two sites both of occupancy 0.5. Bonding to the acetate ligands creates a completely connected three-dimensional structure. All H atoms of the water molecules participate in hydrogen bonding.