Crystal Symmetry of Struvite (Guanite)

Abstract

WE have examined a small cluster of white crystals which were discovered in a can of Japanese crab-meat by Prof. H. E. Fetch, McMaster University, Hamilton, Ontario. Spectrographic analysis showed that the crystals contained both phosphorus and magnesium, and the density, determined by flotation in a heavy liquid, was found to be 1.71 gm. cm.⁻³. The crystals were insoluble in water. The unit cell and systematic absences of X-ray reflexions were determined from a small single crystal using a Buerger precession camera. They are: a ₀ = 6.13 ± 0.02 A., b ₀ = 6.92 ± 0.02 A., c ₀ = 11.19 ± 0.02 A., a ₀:b ₀:c ₀ = 0.883 : 1 : 1.616, hkl no absences, hkO no absences, Okl k + l = 2n + l absent, h0l no absences, h00 no absences, 0k0 k = 2n + 1 absent, h0l no absent, h00 no absence, 0k0 k = 2n + 1 absent, 00l l = 2n + 1 absent. The space group is Pnm2_l and the a ₀ axis has pseudo-hexagonal symmetry.