Journal of Applied Crystallography · 1981 · 30 citations · 0 references
Natural SciencesChemistryCrystal StructureOrganic ChemistryStructure-activity RelationshipsCrystal ChemistryCrystal LatticeCrystal SymmetryCrystallographyMolecular SymmetryStructure DeterminationCrystal AxesCrystal FormCrystal Structure DeterminationCrystal Symmetry AnalysisCrystal Symmetry DeterminationCrystallographic CharacterizationDrug Crystal FormOrthorhombic Crystal Lattices
The powder data for anhydrous theophylline (1,3-dimethylxanthine), C 7 H 8 N 4 O 2 , are reported. It is orthorhombic, Pna 2 1 , with a = 24.628 (4), b = 3.833 (2), c = 8.501 (5) Å; U = 802.49 Å 3 ; Z = 4; D m = 1.478, D c = 1.489 Mg m −3 .