Crystal structures of three β‐halolactic acids: hydrogen bonding resulting in differing Z′.

The crystal structures of three β‐halolactic acids have been determined, namely, β‐chlorolactic acid (systematic name: 3‐chloro‐2‐hydroxypropanoic acid, C3H5ClO3) (I), β‐bromolactic acid (systematic name: 3‐bromo‐2‐hydroxypropanoic acid, C3H5BrO3) (II), and β‐iodolactic acid (systematic name: 2‐hydroxy‐3‐iodopropanoic acid, C3H5IO3) (III). The number of molecules in the asymmetric unit of each crystal structure (Z′) was found to be two for I and II, and one for III, making I and II isostructural and III unique. The difference between the molecules in the asymmetric units of I and II is due to the direction of the hydrogen bond of the alcohol group to a neighboring molecule. Molecular packing shows that each structure has alternating layers of intermolecular hydrogen bonding and halogen–halogen interactions. Hirshfeld surfaces and two‐dimensional fingerprint plots were analyzed to further explore the intermolecular interactions of these structures. In I and II, energy minimization is achieved by lowering of the symmetry to adopt two independent molecular conformations in the asymmetric unit. [ABSTRACT FROM AUTHOR]