Structure of a cavity-encapsulated nanodrop of water

A (H2O)100 nanodrop of water was found in the cavity of a spherical polyoxomolybdate cluster of the type {(Mo)Mo5}12(spacer)30 and structurally characterised. The molecules within the water cluster are arranged in three concentric shells with radii of 3.84–4.04, 6.51–6.83 and 7.56–7.88 Å spanned by 20, 20, and 60 molecules, respectively. The first shell dodecahedron is formed exclusively by 20 hydrogen bonds (O⋯O=2.77–2.92 Å) in the centre and 12 (H2O)5 pentagons (O⋯O=2.66–2.81 Å) formed by hydrogen bonds at the periphery, i.e., the third shell. Each of the H2O molecules of the second (dodecahedral) shell connects the molecules from three different pentagons of the third shell with one molecule of the central dodecahedron.