Cation and anion topotactic transformations in cobaltite thin films leading to Ruddlesden-Popper phases, I. T. Chiu, M. H. Lee, S. Cheng, S. Zhang, L. Heki, Z. Zhang, Y. Mohtashami, P. N. Lapa, M. Feng, P. Shafer, A. T. N’Diaye, A. Mehta, J. A. Schuller, G. Galli, S. Ramanathan, Y. Zhu, I. K. Schuller and Y. Takamura, Physical Review Materials 5, 064416 (2021); Editor’s Suggestion