Similarities with a number of liquid‐crystal systems are revealed by the structural characterization of the low‐temperature phases II—IV of the solid adduct from benzene and hexafluorobenzene (right). As the temperature is raised, increased rotation leads to a reduction in the interactions between neighboring columns of alternating C6H6 and C6F6 molecules. These results could only be obtained by using a combination of powder diffraction techniques with neutrons and synchrotron radiation.

Crystalline layered carbon nitrides can be inter-converted by simple ion exchange process allowing their properties to be tuned.

A strategy of using crystal structure prediction (CSP) methods to determine which, if any, isostructural template could facilitate the first crystallization of a predicted polymorph by vapor deposition is extended to the fenamate family. Mefenamic acid (MFA) and tolfenamic acid (TFA) are used as molecules with minimal chemical differences, whereas flufenamic acid (FFA) shows greater differences in the substituents. The three crystal energy landscapes were calculated, and periodic electronic structure calculations were used to confirm the thermodynamic plausibility of possible isostructural polymorphs to experimentally obtainable crystals of the other molecules. As predicted, a new polymorph, TFA form VI, was found by sublimation onto isomorphous MFA form I, using a recently developed technique. MFA and TFA form a continuous solid solution with the structure of MFA I and TFA VI at the limits, but the isomorphous MFA/FFA solid solution does not extended to a new polymorph of FFA. The novel solid solution structure of TFA and FFA was found, and a new isomorphous polymorph TFA VII was found by sublimation onto this new solid solution template. Sublimation of TFA onto a metal surface at the early stage of deposition gave TFA form VIII. We rationalize the formation of new polymorphs of only TFA.