The reaction of (NH4)2PbCl6 and fuming sulfuric acid (65 % SO3) in a sealed glass tube at 250 °C led to colorless single crystals of Pb[S3O10] (orthorhombic, Pbcn, Z = 4, a = 10.9908(4), b = 8.5549(3), c = 8.0130(3) Å, V = 753.42(5) Å3). The compound shows a three-dimensional linkage of the tenfold oxygen coordinated Pb2+ ions and exhibits the unusual trisulfate anion, [S3O10]2–, that consists of three vertex connected [SO4] tetrahedra. The distances S–O within the S–O–S bridges of the anion are remarkable asymmetric with distances of 155 and 169 pm, respectively. This structural feature is well reproduced by calculations on a PBE0/cc-pVTZ and a MP2/cc-pVTZ level of theory. Similar calculations allow also for an inspection of the yet unknown corresponding acid, H2S3O10. Also for this acid non-symmetric S–O–S bridges are predicted. The thermal behavior of Pb[S3O10] is characterized by the loss of two equivalents of SO3 at low temperature and the decomposition of intermediate Pb[SO4] at higher temperature.