Information card for entry 2018308

Structure parameters

• Chemical name: 3,7-dihydro-1,3-dimethyl-1<i>H</i>-purine-2,6-dione
• Formula: C7 H8 N4 O2
• Calculated formula: C7 H8 N4 O2
• SMILES: c1nc2c(C(=O)N(C(=O)N2C)C)[nH]1
• Title of publication: Polymorphs of anhydrous theophylline: stable form IV consists of dimer pairs and metastable form I consists of hydrogen-bonded chains
• Authors of publication: Khamar, Dikshitkumar; Pritchard, Robin Gavin; Bradshaw, Ian James; Hutcheon, Gillian Ann; Seton, Linda
• Journal of publication: Acta Crystallographica Section C
• Year of publication: 2011
• Journal volume: 67
• Journal issue: 12
• Pages of publication: o496 - o499
• a: 13.158 ± 0.002 Å
• b: 15.63 ± 0.003 Å
• c: 3.854 ± 0.001 Å
• α: 90°
• β: 90°
• γ: 90°
• Cell volume: 792.6 ± 0.3 ų
• Cell temperature: 100 ± 2 K
• Ambient diffraction temperature: 100 ± 2 K
• Number of distinct elements: 4
• Space group number: 33
• Hermann-Mauguin space group symbol: P n a 21
• Hall space group symbol: P 2c -2n
• Residual factor for all reflections: 0.1411
• Residual factor for significantly intense reflections: 0.0881
• Weighted residual factors for significantly intense reflections: 0.1726
• Weighted residual factors for all reflections included in the refinement: 0.2022
• Goodness-of-fit parameter for all reflections included in the refinement: 0.98
• Diffraction radiation wavelength: 0.71073 Å
• Diffraction radiation type: MoKα
• Has coordinates: Yes
• Has disorder: No
• Has Fobs: Yes