The crystal structure of a new type arylarsonic polytungstate[C(NH_)_]_4[p-NH_3C_6H_4As)_2-W_6O_(25)]·4H_O was determined by single-crystal X-ray diffraction analysis.It belongs to triclinic,spacegroup P,with cell dimensions a=12.863(3),b=18.912(3),c=21.383(4)α=91.14(2)°,β=93.65(3)°,γ=92.25(3)°,V=5185.9~3,Z=4,D_c=2.753g/cm~3.The intensity data were collected onan Enraf-Nonius CAD4 diffractometer with Mo Kα radiation.The positions of all tungsten and arsenicatoms were determined by direct method.The other non-hydrogen atoms were revealed by differenceFourier synthesis.The structure was refined by fullmatrix least-squares procedure to a final R value of0.070.The crystal structure contains two similar but nonidentical molecules.Two similar anionsconsist of a ring of six WO_6 octahedra,which are connected with one face-sharing,two corner-sharingsand three edge-sharings,and two p-aminophenylarsonic tetrahedra capped above and below the ring.In each WO_6 ring,four tungsten atoms,which are joined with edge-sharing oxygen atoms,are almostcoplanar,while the two others,which are joined with face-sharing oxygen atoms,protrude out of thering towards the same side.The two arsenic atoms in each anion are not equivalent in their bondingmanner.In each anion,all non-hydrogen atoms of each organic group are in the same plane.Eachmolecule contains one anion,four C(NH_2)_3~+ cations and four water molecules.There are manyhydrogen bonds between cations and anions throughout the whole crystal.The amino groups canaccept protons,so that the charge of the resulting anion decreases and[(RAs)_2W_6O_(25)]~(4-)typecomplexes are formed. The crystal structure of a new type arylarsonic polytungstate [C (NH_) _] _4 [p-NH_3C_6H_4As) _2-W_6O_ (25)] · 4H_O was determined by single-crystal X-ray diffraction analysis.It belongs to triclinic, spacegroup P , with cell dimensions a = 12.863 (3), b = 18.912 (3), c = 21.383 (4) α = 91.14 (2) °, β = 93.65 (3) °, 5185.9 ~ 3, Z = 4, D_c = 2.753g / cm ~ 3. The intensity data were collected onan Enraf-Nonius CAD4 diffractometer with Mo Kα radiation.The positions of all tungsten and arsenic atoms were determined by direct method.The other non- hydrogen atoms were revealed by differenceFourier synthesis.The structure was refined by fullmatrix least-squares procedure to a final R value of0.070.The crystal structure contains two similar but nonidentical molecules. Two similar anionsconsist of a ring of six WO_6 octahedra, which are connected with one face-sharing, two corner-sharings and three edge-sharings, and two p-aminophenylarsonic tetrahedra capped above and below the ring .In each WO_6 ring, four tungsten atoms, whic h are joined with edge-sharing oxygen atoms, are almostcoplanar, while the two others, which are joined with face-sharing oxygen atoms, protrude out of thering towards the same side. The two arsenic atoms in each anion are not equivalent in their bondingmanner . Each of each anion, all non-hydrogen atoms of each organic group are in the same plane. One molecule contains one anion, four C (NH_2) _3 ~ + cations and four water molecules. There are many hydrogen bonds between cations and anions throughout the whole crystal.The amino groups canaccept protons, so that the charge of the resulting anion decreases and [(RAs) _2W_6O_ (25)] ~ (4-) typecomplexes are formed.