Neutron diffraction study of squaric acid (3,4-dihydroxy-3-cyclobutene-1,2-dione)
A neutron diffraction study of squaric acid (C/sub 4/H/sub 2/O/sub 4/; 3,4-dihydroxy-3-cyclobutene-1,2-dione) at 25degreeC has been carried out. Space group P2/sub 1//m, a=6.143(2), b=5.286(2), c=6.148(2) A, ..beta..=89.96(2) degree, Z=2. The structure has been refined with 67 variable parameters on 1026 reflections, comprising one hemisphere of the reciprocal lattice to yield a conventional crystallographic R value of 0.025. An anisotropic extinction correction was applied, and 66 reflections severely effected by extinction were not used in the final cycles of refinement. The squaric acid molecules are linked by strong hydrogen bonds to form infinite planar layers in the crystallographic mirror planes. The hydrogen bond lengths are HxxxO 1.034 and OxxxO 2.554 A, the O-HxxxO angle is 177.5degree. Average intramolecular bond distances are C--O 1.288, C=O 1.229, C--C 1.500 and 1.462, and C=C 1.414 A.
- Research Organization:
- Department of Chemistry, University of Oslo, Oslo 3, Norway
- OSTI ID:
- 7305407
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 66:10; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
BOND LENGTHS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
DIFFRACTION
NEUTRON DIFFRACTION
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
SCATTERING
STRUCTURAL CHEMICAL ANALYSIS