Synthesis, Crystal Structure, and Characterization of a New Metal Borophosphate: Pb^II₄{Co₂[B(OH)₂P₂O₈](PO₄)₂}Cl

A new metal borophosphate Pb-4(II){Co-2[B(OH)(2)P2O8](PO4)(2)}Cl (1), containing both Pb2+ cations and Cl- anions, was hydrothemially synthesized and characterized by powder X-ray diffraction, ICP, TG/DTA, and FTIR spectroscopic analyses. The crystal structure determination from single-crystal X-ray diffraction reveals that compound 1 crystallizes in the trigonal space group R (3) over barc (No. 167), a = 9.7513(7) angstrom, c = 91.060(13) angstrom, V = 7498.7(13) angstrom(3) and Z = 18. Its structure features a new cobalt borophosphate layer {Co-2[B(OH)(2)P2O8](PO4)(2)}(7-) built up from CoO5 square pyramids, [B(OH)(2)P2O8](5-) borophosphate timers and PO4 tetrahedra. Extraframework Pb2+ and Cl- ions are located at the vacancy of layers to achieve the charge neutrality of the framework. Magnetic measurements indicate that antiferromagnetic interactions exist between Co2+ ions with a negative Weiss constant of -20.3 K