Crystal data for tris (1, 10-phenanthroline)–bis(sulfuric acid) dihydrate, 3C₁₂H₈N₂.2H₂SO₄.2H₂O, and 1, 10-phenanthroline–bis(sulfuric acid), C₁₂H₈N₂.2H₂SO₄

The powder data for the title compounds are reported. They are monoclinic, Bb or B2/b, with, for 3C₁₂H₈N₂.2H₂SO₄.2H₂O, a = 20.87 (1), b = 14.581 (9), c = 11.458 (7) Å, γ = 108.32 (6)°, Z = 4, D_m = 1.58, D_c = 1.55 Mg m⁻³, and, for C₁₂H₈N₂.2H₂SO₄, a = 17.39 (3), b = 15.38 (4), c = 6.85 (1) Å, γ = 124.9 (1)°, Z = 4.