gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1995.059.397.10 Experimental Mineralogy Synthesis and Rietveld Crystal Structure Refinement of Mackinawite, Tetragonal FeS Lennie A. R. * Redfern S. A. T. † Schofield P. F. ‡ Vaughan D. J. * Department of Earth Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK Department of Mineralogy, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK 12 1995 59 397 677 683 24 1 1995 6 4 1995 Copyright © 1995, The Mineralogical Society 1995 Abstract

Mackinawite, tetragonal FeS, has been synthesised by reacting iron with Na2S solutions. A Rietveld structure refinement of X-ray powder diffraction data, recorded using X-rays monochromated from synchrotron radiation with a wavelength of 0.6023 Å, has been performed. The structure has been refined in the tetragonal space group, P4/nmm, and has the following cell parameters: a = 3.6735(4), c = 5.0328(7) Å, V = 67.914(24) Å3. Our refinement shows that the FeS4 tetrahedron in mackinawite is almost perfectly regular, with a much smaller distortion than has been previously reported. An improved X-ray diffraction data set is provided.

 Keywords mackinawite Rietveld structure refinement synthesis