The sixth blind test of organic crystal structure prediction (CSP) methods has been held, with five target systems: a small nearly rigid molecule, a polymorphic former drug candidate, a chloride salt hydrate, a co-crystal and a bulky flexible molecule. This blind test has seen substantial growth in the number of participants, with the broad range of prediction methods giving a unique insight into the state of the art in the field. Significant progress has been seen in treating flexible molecules, usage of hierarchical approaches to ranking structures, the application of density-functional approximations, and the establishment of new workflows and `best practices' for performing CSP calculations. All of the targets, apart from a single potentially disorderedZ′ = 2 polymorph of the drug candidate, were predicted by at least one submission. Despite many remaining challenges, it is clear that CSP methods are becoming more applicable to a wider range of real systems, including salts, hydrates and larger flexible molecules. The results also highlight the potential for CSP calculations to complement and augment experimental studies of organic solid forms.

From first principles calculations, we investigate the stability and physical properties of single-layer $h$-BN sheet chemically functionalized by various groups, viz. H, F, OH, CH${}_3$, CHO, CN, NH${}_2$, etc. We find that full functionalization of $h$-BN sheet with these groups leads to decrease in its electronic band gap, albeit to different magnitudes varying from 0.3 eV to 3.1 eV, depending upon the dopant group. Functionalization by a CHO group in particular leads to a sharp decrease in the electronic band gap of the pristine BN sheet to ∼0.3 eV, which is congenial for its usage in transistor-based devices. For the optimized structure of the sheet, the calculated phonon frequencies corresponding to all the vibrational modes turn out to be real (positive), thereby suggesting their inherent stability. The chemisorption energies of these groups with the B and N atoms of the sheet are found to lie in the range of 1.5–6 eV. The optical absorption and conductivity of these functionalized sheets under polarized light are found to be much higher than that of the native BN sheet.

The leaf-templated and oxygen vacancy engineered CaTiO₃ showed excellent structural stability but with loss in morphology for the studied binary phase photocatalytic reactions.