Ba 4 Ni 3 F 14 ·H 2 O: a ferrimagnetic compound with a staircase kagomé lattice.

A new crystalline fluoride Ba 4 Ni 3 F 14 ·H 2 O was found to exhibit a rare S = 1 staircase kagomé lattice built by Ni 2+ ions. Magnetic measurements indicate a ferrimagnetic transition at ∼28 K, while 1/3 plateau can be observed from the magnetization curve. We suggest that the hydrogen-bond interactions of O-H⋯F pathways may play an important role for magnetic properties of the system.