title: Resorcinol Crystallization from the Melt: A New Ambient Phase and New "Riddles".
abstract: Structures of the α and β phases of resorcinol, a major commodity chemical in the pharmaceutical, agrichemical, and polymer industries, were the first polymorphic pair of molecular crystals solved by X-ray analysis. It was recently stated that "no additional phases can be found under atmospheric conditions" (Druzbicki, K. et al. J. Phys. Chem. B 2015, 119, 1681). Herein is described the growth and structure of a new ambient pressure phase, ε, through a combination of optical and X-ray crystallography and by computational crystal structure prediction algorithms. α-Resorcinol has long been a model for mechanistic crystal growth studies from both solution and vapor because prisms extended along the polar axis grow much faster in one direction than in the opposite direction. Research has focused on identifying the absolute sense of the fast direction-the so-called "resorcinol riddle"-with the aim of identifying how solvent controls crystal growth. Here, the growth velocity dissymmetry in the melt is analyzed for the β phase. The ε phase only grows from the melt, concomitant with the β phase, as polycrystalline, radially growing spherulites. If the radii are polar, then the sense of the polar axis is an essential feature of the form. Here, this determination is made for spherulites of β resorcinol (ε, point symmetry 222, does not have a polar axis) with additives that stereoselectively modify growth velocities. Both β and ε have the additional feature that individual radial lamellae may adopt helicoidal morphologies. We correlate the appearance of twisting in β and ε with the symmetry of twist-inducing additives.
authors.affiliation: Department of Geosciences, Stony Brook University , Stony Brook, New York 11794, United States.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Chemistry and Molecular Design Institute, New York University , New York City, New York 10003, United States.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Shtukenberg
authors.affiliation: Curtin Institute for Computation, Nanochemistry Research Institute and Department of Chemistry, Curtin University , P.O. Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Damien J
authors.initials: DJ
authors.lastname: Carter
authors.affiliation: Department of Chemistry and Courant Institute, New York University , New York City, New York 10003, United States.
authors.forename: Tang-Qing
authors.initials: TQ
authors.lastname: Yu
authors.affiliation: Department of Chemistry and Molecular Design Institute, New York University , New York City, New York 10003, United States.
authors.forename: Jingxiang
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Courant Institute, New York University , New York City, New York 10003, United States.
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.affiliation: Curtin Institute for Computation, Nanochemistry Research Institute and Department of Chemistry, Curtin University , P.O. Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Paolo
authors.initials: P
authors.lastname: Raiteri
authors.affiliation: Department of Geosciences, Stony Brook University , Stony Brook, New York 11794, United States.
authors.forename: Artem R
authors.initials: AR
authors.lastname: Oganov
authors.affiliation: Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion Israel Institute of Technology , Haifa 32000, Israel.
authors.forename: Boaz
authors.initials: B
authors.lastname: Pokroy
authors.affiliation: Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion Israel Institute of Technology , Haifa 32000, Israel.
authors.forename: Iryna
authors.initials: I
authors.lastname: Polishchuk
authors.affiliation: School of Chemistry, University of Southampton , Highfield, Southampton, SO17 1BJ, United Kingdom.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bygrave
authors.affiliation: School of Chemistry, University of Southampton , Highfield, Southampton, SO17 1BJ, United Kingdom.
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Day
authors.affiliation: Curtin Institute for Computation, Nanochemistry Research Institute and Department of Chemistry, Curtin University , P.O. Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Rohl
authors.affiliation: Department of Chemistry and Courant Institute, New York University , New York City, New York 10003, United States.|New York University-East China Normal University Center for Computational Chemistry at NYU Shanghai , 3663 Zhongshan Road North, Shanghai 200062, China.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Tuckerman
authors.affiliation: Department of Chemistry and Molecular Design Institute, New York University , New York City, New York 10003, United States.
authors.forename: Bart
authors.initials: B
authors.lastname: Kahr