Precision of a crystal structure derived from a synchrotron X-ray powder pattern. The structure of Barium oxalate hydrate, BaC2O4·2H2O

Abstract

The crystal structure of barium oxalate hydrate, BaC204.2H20, was reinvestigated using a synchrotron X-ray powder pattern and a single crystal X-ray data set. The compound is monoclinic, a = 7.538(l), b = 11.062(l), c = 7.105(1) A, 0 = 105.42(l)", space group P21/c, with Z = 4. The precision of the structure arrived at with the synchrotron X-ray powder pattern is not as high as that obtained with the single crystal X-ray data. The barium atoms are bonded to the. oxalate ions and to the water molecules with nine barium oxygen-bonds in the range 2.71(l)-2.97(l)A. The structure has hydrogen bonds in the range 2.72(2)-2,91(2)A, and the oxalate ion has only a minor deviation from planarity.

Growth aspects of barium oxalate monohydrate single crystals in gel medium

“…With Z = 4 [22], the calculated density value of the barium oxalate crystal (3.483 g/cm 3 ) is almost equal to the reported bulk value [23].…”

Synthesis and characterization of the barium oxalates BaC2O4·0.5H2O, α-BaC2O4 and β-BaC2O4

“…Barium oxalate forms four hydrates, of which hydrogen bonds have been studied of BaC 2 O 4 Á3.5D 2 O (Neder et al, 1997), BaC 2 O 4 Á2D 2 O (Christensen et al, 1995) and BaC 2 O 4 ÁD 2 O (Christensen, 1992) by neutron powder diffraction analysis. The crystal structure of the barium oxalate hemihydrate BaC 2 O 4 Á0.5H 2 O (Mutin et al, 1981) has been studied by single-crystal X-ray diffraction analysis.…”