title: On the polymorphism of benzocaine; a low-temperature structural phase transition for form (II).
abstract: A low-temperature structural phase transition has been observed for form (II) of benzocaine (BZC). Lowering the temperature doubles the b-axis repeat and changes the space group from P2(1)2(1)2(1) to P112(1) with gamma now 99.37 degrees. The structure is twinned, the twin rule corresponding to a 2(1) screw rotation parallel to a. The phase transition is associated with a sequential displacement parallel to a of zigzag bi-layers of ribbons perpendicular to b*. No similar phase transition was observed for form (I) and this was attributed to the different packing symmetries of the two room-temperature polymorphic forms.
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia. echanj@rsc.anu.edu.au
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Chan
authors.forename: A David
authors.initials: AD
authors.lastname: Rae
authors.forename: T Richard
authors.initials: TR
authors.lastname: Welberry
mesh_terms: D001566:Benzocaine / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D044367:Phase Transition; D013696:Temperature
chemical_list: D001566:Benzocaine