The first structurally characterised example of a 2-D clathrate hydrate spontaneously assembles when [CuF(tptm)] (tptm = tris(2-pyridylthio)methyl) crystallises from toluene/water solutions to produce a material in which planar arrays of [CuF(tptm)] sandwich and hydrogen bond to continuous 2-D sheets of water that incorporate toluene molecules at regular intervals.