The anions [(ZrOH(CO 3) 3) 2] 6− and [(ZrOH(C 2O 4) 3) 2] 6− : single crystal X-ray diffraction studies of the complexes guanidinium zirconium carbonate [(C(NH 2) 3) 3ZrOH(CO 3) 3·H 2O] 2 and sodium zirconium oxalate Na 6(ZrOH(C 2O 4) 3) 2·7H 2O

Abstract

The complex [(C(NH 2) 3) 3ZrOH(CO 3) 3·H 2O] 2 ( A) has been shown by means of a single crystal X-ray diffraction study to contain [C(NH 2) 3] + cations and dimeric anions of formulation [(ZrOH(CO 3) 3) 2] 6−. The anion is centrosymmetric with each metal being bonded to two bridging OH groups and three chelating CO 2− 3 ions. The Zr atoms are thus eight coordinate with a dodecahedral environments. The ZrO distances formed by the bridgng OH groups are shorter than those formed through zirconiu carbonate interactions. The non-bonded Zr…Zr distance is 3.47(2) Å. An infrared spectroscopic investigation of A provides data which support the findings of the crystallographic study. Likewise the complex Na 6(ZrOH(CO 2O 4) 3) 2·7H 2O ( B) contains the anion [(ZrOH(C 2O 4) 3) 2] 6−. This anion is structurally related to the anion in A as each Zr atom has an eight-coordinate dodecahedral environment being bonded to two bridging OH groups and three chelating oxalate ligands, but has no imposed crysallographic symmetry. The Zr…Zr non-bonded distance is 3.50(1) Å. The OZrO bridge angles are 69.7(4)° and A and 67.4(3)° in B.