Hydrothermal synthesis and structures of two zero-dimensional zinc phosphate polymorphs

Abstract

Two polymorphs of zero-dimensional zinc phosphate with the formula, ⁰_∞[Zn(2,2'-bipy)(H₂PO₄)₂], have been synthesized employing hydrothermal technique and their structure determined by single crystal X-ray diffraction. Both the structures consists of ZnO₃N₂ distorted trigonal-bipyramidal and PO₂(OH)₂ tetrahedral units linked through their vertices giving rise to a zero-dimensional molecular zinc phosphate. The structures are stabilized by extensive hydrogen bond interactions between zero-dimensional monomers. The structures display subtle differences in their packing created by hydrogen bond interactions. Crystal data: polymorph I, triclinic, space group P 1 (No. 2) a = 7.5446(15) Å, b = 10.450(2) Å, c = 10.750(2) Å, α=67.32(3)°, β=81.67(3)°, γ=69.29(3)°, V = 731.4(3) ų, Z=2; polymorph II, triclinic, space group (No. 2), P 1 (No. 2), a = 8.664(1) Å, b = 8.849(2) Å, c = 10.113(2) γ, α=97.37(2)° β=100.54(2)°, γ=100.98(2)°,V = 737.5(3) ų, Z=2.