The tetrathiotungstate salt of ammonia has been prepared. Zero-layer Weissenberg photographs have been used to establish that this material is orthorhombic with a = 9.623 Å, b = 12.406 Å, and c = 7.055 Å with space group Pn21a—C2v9 or Pnma—D2h16. The data have been used to index the Debye–Scherrer pattern.