**Acknowledgments**

We thank kindly our former collaborators Said Hamad, Eleonora Spano, Stefan T. Bromley, Stephen A. Shevlin, Matthew B. Watkins, and Abdullah A. Al-Sunaidi, discussions with who have been inspiring and instrumental for us undertaking this research. We also thank EPSRC for providing the funding for Matthew Farrow and Scott Woodley on grant numbers EP/I03014X9 and EP/K038958; John Buckeridge and Alexey Sokol on grant number EP/IO1330X; and Andrew Logsdail on grant numbers EP/I030662/1 and EP/K038419/1. The authors also acknowledge the use of the UCL Legion High Performance Computing Facility (Legion@UCL) and associated support services; the IRIDIS cluster provided by the EPSRC funded Centre for Innovation (EP/K000144 and EP/K000136); this work made use of the facilities of HECToR and ARCHER, the UK's national high-performance computing service through membership of the UK's HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202).

#### **Author Contributions**

The structures were constructed by Scott M. Woodley. The interatomic potential calculations were performed by Scott M. Woodley and Alexey A. Sokol. The double bubble cluster calculations were performed by Matthew R. Farrow. The double bubble framework calculations were performed by John Buckeridge. The literature was researched by Andrew J. Logsdail and David O. Scanlon. Expertise both in relevant materials science and methodology was provided by C. Richard A. Catlow and Scott M. Woodley. Vital contributions to simulations design, the data analysis and preparation of the manuscript were made by all of the authors.

#### **Conflicts of Interest**

The authors declare no conflict of interest.
