Structures of the Triclinic and the Monoclinic Modification of Divascan®

Abstract Trielinic modification: C 12 N 4 O 3 H 16 . M r = 264.26, triclinic P 1 , a = 7.702(3), b = 9.420(11), c = 10.893(8) A, α = 73.37(8), β = 82.22(5), γ = 66.30(6)°, V = 638(1) A 3 , Z = 2, D m = 1.360 Mg m −3 , D x = 1.362 Mg m −3 , λ(MoK α ) = 0,71062 A, μ = 0.1084 mm −1 , F (000) = 280, T = 296 K, final R = 0.0742, w R = 0.0758 for 1842 reflections. Monoclinic modification: C 12 N 4 O 3 H 16 ·, 3/2H 2 O, M r = 291.28, monoclinic P 2 1 ,/c, α = 14.075(5), b = 12.631(6), c = 16.234(5) A, β = 99.25(3)°, V = 2849(1) A 3 , Z = 8, D m = 1.338 Mg m −3 , D m = 1.359 Mg m −3 , λ(MoK α ) = 0.71062 A, μ = 0.1134 mm −1 , F(000) = 1240, T = 296 K, final R = 0.0557, wR = 0.0691 for 1266 reflections. Comparison of the two independent Divascan® molecules of the monoclinic modification with the one of the triclinic modification demonstrates good agreement of related bond distances and angles in the molecules. Disorder of the hydroxyl groups of one Divascan® molecule of the monoclinic modification is announced by high vibration parameters of the related oxygen atom and a very short CO distance, which is not adequate to a real CO bond length.