As for the relative size of the discussed moieties, introducing oxygen atom decreased both C1-C3 (l) and C2-C4/O (r) interatomic distances (numeration of the parent cyclobutane ring was preserved). For the CF2 moiety, the corresponding effects were opposite, i.e., decrease for r and increase for l. Also, the 3,3-diFOx moiety had the second lowest value of maximum fragment diameter (R) withing the series studied. Analysis of the Hirshfeld surface of (S*,S*)-4c (Figure , B) demonstrated high involvement of the Oxygen and Nitrogen atoms into the formation of intermolecular contacts in the solid state (red spots), whereas the Fluorine atoms did not participate in these interactions (blue areas).