TRANS-4,4'-DIFLUOROCHALCONE;4,4'-DIFLUOROCHALCONE;4-FLUOROBENZYLIDENE-(4-FLUOROACETOPHENONE);2-(4-FLUOROBENZAL)-4'-FLUOROACETOPHENONE;2-(4-FLUOROBENZYLIDENE)-4'-FLUOROACETOPHENONE;1-(4-Fluorophenyl)-3-(4-fluorophenyl)-2-propen-1-one;4,4'-difluorochalconepredomi];4,4'-DIFLUOROCHALCONE, 98%, PREDOMINANTLY TRANS