Abstract:
Many details including the reaction scheme of crystal synthesis in a recent paper reporting optical and mechanical properties of 1-(4-fluorostyryl)-4-nitrostilbene (FNS) single crystal, by Dinakaran and Kalainathan (Optik, 2013 [1]), are very similar to those reported earlier by the same authors for another crystal namely 4-fluoro-4'-nitrostilbene (FONS). FNS is not a new NLO crystal but a new code for FONS with a different and obviously wrong chemical name. FNS crystal is a non-existent compound because substitution of a (4-fluorostyryl) moiety at the 1-position of 4-nitrostilbene will result in pentavalency for carbon.
