Crystal structure of anhydrous barium methacrylate

Abstract

The crystal structure of anhydrous barium methacrylate, Ba[O₂, C·C(:CH₂)CH₃]₂ has been determined by the heavy-atom method from X-ray diffractometer data and refined by full-matrix least squares to R 0.042 for 1 578 reflections. Crystals are monoclinic, space group P2₁/c, a= 12.162(1), b= 8.017(1), c= 10.373(1)Å, β= 102.87(1)°, Z= 4. The structure is comprised of sheets of almost coplanar barium ions bridged as an infinite two-dimensional polymer normal to a* by the carboxylate groups. Ba–O distances range from 2.766 to 3.030(5)Å about the irregularly eight-co-ordinate cation; in the ligands, the central C–C bond is long [1.498(10), 1.511 (9)Å] and one of the ligands is grossly twisted about the bond.