An Organically Templated Copper Pentaborate with Infinite Metallo‐chains: [Cu(C 3 N 2 H 4 ) 4 ][Cu(CH 3 COO) 2 (C 3 N 2 H 4 ) 2 (H 2 O) 2 ][B 5 O 6 (OH) 4 ] 2

A novel organically templated copper pentaborate, [Cu(C 3 N 2 H 4 ) 4 ][Cu(CH 3 COO) 2 (C 3 N 2 H 4 ) 2 (H 2 O) 2 ]‐ [B 5 O 6 (OH) 4 ] 2 , was synthesized by hydrothermal reaction and characterized by elemental analysis, single‐crystal X‐ray diffraction, FT‐IR spectroscopy, Raman spectroscopy and TGA. The crystal structure of this compound consists of two copper‐centered polyhedra and two discrete [B 5 O 6 (OH) 4 ] − pentaborate anions, which are linked together through intensive hydrogen bonding interactions, forming a 3D framework with large channels along c axis. The discrete pentaborate anions form infinite layers by hydrogen bonds. Moreover, the two crystallographically different octahedral coppers are connected by common oxygen atom to form an infinite chain.