A new 3D heteropolyoxotungstate, (NH4)2{[Ni(H2O)3]2[TeW6O24]} · H2O (1), has been isolated from hydrothermal reactions and characterized by elemental analyses, IR spectra and X-ray crystallography. Single-crystal X-ray diffraction analysis reveals that compound 1 possess unusual (3,6)-connected networks constructed from Anderson-type anions [TeW6O24]6- and nickel cations. The compound exhibits pyrite-like topology in which [TeW6O24]6- anions act as 6-connecting sites and nickel cations act as 3-connecting sites. The magnetic properties of 1 are also presented. [ABSTRACT FROM AUTHOR]