A　novel　inorganic-organic　hybrid　polyoxotungstate　H-4[Ni(en)(2)](2)[Ni(en)(dap)](2)[Ni(dap)(2)](2)[Ni-4(en(2))(PW9O34)(2)]{[Ni(H2O)(5)](2)[Ni-4(en)(2)(PW9O34)(2)]}center　dot　12H(2)O　(1,　en　=　ethylenediamine,　dap　=　1,2-diaminopropane)　has　been　successfully　synthesized　under　hydrothermal　conditions　and　structurally　characterized　by　single-crystal　X-ray　diffraction,　powder　X-ray　diffraction,　infrared　spectroscopy,　elemental　analysis　and　thermogravimetric　analysis,　respectively.　Single-crystal　structure　analysis　reveals　that　I　exhibits　a　2-D　network　structure　based　on　two　kinds　of　tetra-Ni-substituted　sandwich-type　Keggin　polyoxoanions　linked　by　different　types　of　Ni-organoamine　complexes.　(C)　2016　Elsevier　B.V.　All　rights　reserved.