Unlocking a Chemically Fertile Moderate-Pressure Regime in High-Pressure Borate Synthesis Using Soft-Chemistry Precursors

symmetry and feature large 12- and 16-membered ring channel topologies within fully tetrahedral borate frameworks, an outcome that contrasts with the expected densification under compression. Temperature-dependent phase evolution further reveals that moderate HP/HT conditions can stabilize partially dehydrated, metastable frameworks inaccessible at ambient pressure. These results demonstrate that precursor-controlled kinetics can redefine accessible phase space in HP/HT synthesis, establishing moderate-pressure regimes as productive platforms for discovering structurally complex borates and beyond.