Structure determination of anhydrous acid strontium oxalate by conventional X-ray powder diffraction

摘要

The anhydrous acid strontium oxalate Sr(HC_2O_4)·1/2(C_2O_4) was obtained by thermal decomposition of the hydrated acid strontium oxalate Sr(HC_2O_4)·1/2(C_2O_4)·H_2O. This non-hygroscopic compound crystallizes in the space group P 2_1/c (No. 14) with unit cell parameters: α = 0.79661(7) nm, b=0.9205(1) nm, c=0.731 98(8) nm, and β= 102.104(8)°. Final refinement of the X-ray powder data yielded R_B = 3.2% and R_(wp)= 11.1% (background-corrected data). In this structure, Sr is eight-fold coordinated by O. These polyhedra are connected together by edge-sharing to form two-dimensional (2D) layers along the bc-plane, which means that there is an increased dimensionality from 1D to 2D with decreasing water content of the acid oxalates.