title: Optical characterization of a low solubility organic compound.
abstract: The X, Y, and Z principal vibration directions along with the principal refractive indexes, optic angle, optical sign, birefringence, optical orientation, and crystal system for the low solubility compound 5-(tetradecyloxy)-2-furancarboxylic acid were determined with a polarizing microscope and spindle stage. The X and Z principal vibration directions are not coincident with the a and c crystallographic axes; however, the Y direction is considered to be coincident with the b axis. Therefore, the crystal is assigned to the monoclinic crystal system. The bladed/lath-shaped crystals rest on one of the two large orthopinacoid (100) faces and present the microscopist with a single plane of optical symmetry. A beta refractive index of 1.555 is observed with the crystal axis of elongation parallel to the polarizer, and a gamma of 1.600-1.660 is observed in the contiguous extinction position. Determination of the optic angle principal vibration directions, and principal refractive indexes was facilitated by mounting the crystals on a spindle stage for rotation about the b crystallographic axis (optic normal).
mesh_terms: D003460:Crystallization; D005663:Furans / Q000032:analysis*; D009904:Optical Rotation; D012031:Refractometry; D012995:Solubility; D013501:Surface-Active Agents; D014867:Water
chemical_list: D005663:Furans; D013501:Surface-Active Agents; D014867:Water; C014289:5-(tetradecyloxy)-2-furancarboxylic acid