L-2-aminobutyric acid: two fully ordered polymorphs with Z' = 4
Related Experiment Video
Updated: Jun 14, 2026

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
1Department of Chemistry, University of Oslo, 1033 Blindern, Oslo N-0315, Norway. c.h.gorbitz@kjemi.uio.no
Abstract:
The crystal structure of L-2-aminobutyric acid, an L-alanine analogue with an ethyl rather than a methyl side chain, has proved elusive owing to problems growing diffraction quality crystals. Good diffraction data have now been obtained for two polymorphs, in space groups P2(1) and I2, revealing surprisingly complex, yet fully ordered crystalline arrangements with Z' = 4. The closely related structures are divided into hydrophilic and hydrophobic layers, the latter being the thinnest ever found for an amino acid (other than alpha-glycine). The hydrophobic layers furthermore contain conspicuous pseudo-centers-of-symmetry, leading to overall centrosymmetric intensity statistics. Uniquely, the four molecules in the asymmetric unit can be divided into two pairs that each forms an independent hydrogen-bond network.
Related Concept Videos
Structure of Amines
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Nomenclature of Aryl and Heterocyclic Amines
Isomerism in Alkenes
An isomer is called cis-2-butene when the methyl groups are on the same side of the double bond, and the other stereoisomer, in which methyl groups are on the opposite side of the double bond, is called trans-2-butene. The cis and trans stereoisomers are not...
Molecules with Multiple Chiral Centers
Basicity of Heterocyclic Aromatic Amines

