A 3,4-Connected Beryllium Phosphite Framework Containing 24-Ring Channels with a Very Low Density

A new three-dimensional open-framework beryllium phosphite with honeycomb-like channels has been prepared under solvothermal conditions. The alternation of a 24-ring window and a 30-ring window along its extra-large channel is unprecedented in open-framework materials. The compound has a very low density of 1.369 g cm–3 by integrating an extra-large-pore, interrupted 3,4-connected framework and lightweight beryllium metal in its crystalline structure.