The authors regret that there is an error in writing the crystal structure in the article. The authors would like to address as follows:

The presented XRD and TEM results revealed a hexagonal crystal structure. The following analyses including the identification of the lattice parameters and the DFT calculation were based on a hexagonal lattice. Therefore, the HCP (hexagonal close-packed) structure mentioned in the article should be regarded as a hexagonal structure. The HCP term used in the introduction, where the article from Joshua Gild et al. was cited, should also be regarded as hexagonal AlB2 structure.

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.