Crystal structure determination of barium Oxalate, BaC2O4 · 3.5 H2O/D2O

Abstract

Abstract The crystal structure of barium oxalate hydrate, BaC2O4 · 3.5 H2O, was solved using both synchrotron X-ray powder diffraction data and neutron powder diffraction data of BaC2O4 · 3.5 D2O, and synchrotron X-ray single diffraction data, measured on a microcrystal with a mean diameter of 30 μm. The compound is monoclinic, a = 13.445(5) Å, b = 7.669(4) Å, c = 15.018(6) Å, β = 113.92(2)° from the single crystal data, space group C2/c, No. 15, Z = 8, F(000) = 1080, V = 1415.36 Å3, Dx = 2.707 Mg m−3. The precision of the structure determined with the synchrotron X-ray single crystal diffraction data is higher than that obtained from the neutron powder diffraction data. The barium atoms are bonded to the oxalate anions and to the water molecules with ten barium oxygen bonds in the range 2.794(3) Å to 2.974(3) Å. The structure has hydrogen bonds in the range 2.732(4) Å to 2.855(5) Å, and the oxalate ion is essentially planar.