The crystal structure of calcium oxalate trihydrate, grown on whitlockite by reaction with oxalic acid, was determined utilizing 697 independent reflections and converged to R = 0.034. Important parameters are triclinic space group P1, a 7.145(6), b 8.600(7), c 6.099(5), α 112.30(5), β 108.87(5), γ 89.92(5), with 2Ca(H2O)3(C2O4) in the unit cell.

The structure is based on dimers of edge-linked square antiprisms of composition 0[Ca2ϕ14] where ϕ = oxygen ligand which is linked to oxalate groups or water molecules to form a sheet parallel to {100}. In weddellite, square antiprisms link to form a 1[Ca2ϕ12] chain and in whewellite a related polyhedron of order 8 links to form 2[Ca2ϕ10] sheet. It is not topologically possible to construct the series of structures by condensation of polyhedra alone since in each case some rearrangement of the water molecules is necessary.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.