A novel, two-dimensional tellurite of molybdenum(VI), (NH4)(6)Mo8Te8O43. H2O, has been isolated as single crystals in a hydrothermal reaction and characterized by single-crystal X-ray diffraction, infrared spectroscopy, and thermal analysis. Pertinent crystal data are as follows: trigonal space group P (3) over bar, a = 12.124(4) Angstrom, c = 8.130(3) Angstrom, Z = 1. Its structure consists of (Mo8Te8O43)(6-) layers interleaved with ammonium ions, The novel feature of the anionic layer is that it contains two anions, discrete [Mo2O7](2-) anions residing in an extended framework of (Mo6Te8O36)(4-) anions made by corner connection of edge-shared bi-octahedral Mo2O10 units, TeO3 pyramids, and TeO4 units with SF4 geometry. Its decomposition temperature is 371 degrees C.