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

Improved powder X-ray diffraction (XRD) data for franzinite, the ten-layer member of the cancrinite group of minerals, were obtained using an automated parallel-beam powder diffractometer with a capillary mount. The cell parameters of franzinite were found to be a =12.8976(3) A, c=26.5040(8) A, V=3818.2(2) A^3 in space group P321, while the strongest reflections were at 3.725(100), 3.809(65), 3.562(56), 3.586(55), 2.662(42), 2.150(31) and 3.302(30) A. The new results include an increased number of indexed peaks, improved figures-of-merit with respect to PDF 30-1170 and intensities validated by Rietveld refinement.