Zr 6 O 8 core cluster with formula unit [Zr 6 O 4 (OH) 4 (OH 2 ) 8 (CH 3 COO) 4 (SO 4 ) 4 ]· n H 2 O obtained under mild conditions.

During attempts to synthesize zirconium-based MOFs, we have obtained a new crystal structure of the cluster with Zr 6 O 8 core and formula unit [Zr 6 O 4 (OH) 4 (OH 2 ) 8 (CH 3 COO) 4 (SO 4 ) 4 ]· n H 2 O. Unlike other systems, mild conditions were employed in this case; no strong acids or hydrothermal conditions were required. The molecular assembly in the crystal is characterized by strong O-H⋯O hydrogen bonds connecting neighboring molecules, allowing the formation of a three-dimensional maze of tunnels with H 2 O molecules stabilizing the framework. Noteworthy, at 100 °C, the strong Zr 6 O 8 core and the O-H⋯O hydrogen bonds help form a system where the molecular cluster is conserved, but the long-range order is lost. FT-IR, Raman, TGA, DSC, and X-ray diffraction techniques were used to characterize the title compound.