A　new　organically　templated　open-framework　zinc　phosphate,　[C6N3H18]3+[Zn4(PO4)(HPO4)4]3-　·　2H2O,　has　been　synthesized　under　hydrothermal　conditions.　The　structure　was　determined　by　single-crystal　X-ray　diffraction.　It　crystallizes　in　the　triclinic　system,　space　group　P-1　(No.　2),　a　=　8.2130(6),　b　=　10.0257(7),　c　=　15.5133(7)　A,　α　=　80.842(3),　β　=　75.671(4),　γ　=　89.020(5)°,　V　=　1221.54(14)　A3,　Z　=　2.　The　tetrahedral　linkages　between　ZnO4,　PO4　and　HPO4　moieties　have　resulted　in　a　complex　three-dimensional　network　encapsulating　extra-framework　1-(2-aminoethyl)piperazine　and　water　molecules.　The　framework　is　characterized　by　the　extra-large　20-ring　channels　running　along　the　[1　0　0]　direction.　©　2006　Elsevier　Inc.　All　rights　reserved.