Fig. 1: Construction of NKM-908.

a The tetratopic ligand H4NDTB in NKM-908. b The 8-connected Zr6 cluster in NKM-908. c Crystal structure of NKM-908 viewed along the c axis. For clarity, the hydrogen atoms were omitted. d The csq topology network of NKM-908. e PXRD patterns of NKM-908. f N2 sorption isotherms of NKM-908 under 77 K (The inset shows the corresponding pore size distribution).