Re: Quantitative analysis of Iron sulfides

Simon Redfern ( satr@esc.cam.ac.uk )
Wed, 30 Sep 1998 15:27:08 +0100

At 16:09 30/09/98 +0200, you wrote:
>>I could not find a reference for the atomic coordinates of greigite,
>>does anyone know where to find this information?
>
>Greigite (Fe3S4) is said to have the spinel structure, Fd3m,
>a ~ 9.88 Angstroms. No atomic coordinate available, but 96
>spinel entries are in ICSD.
>

For a discussion of the structure of greigite, a thiospinel, and its
relationship to the structure of mackinawite, see:

A R Lennie, S A T Redfern, P E Champness, C P Stoddart, P F Schofield, D J
Vaughan (1997) Transformation of mackinawite to greigite: an in situ X-ray
powder diffraction and transmission electron microscopy study. Am Mineral
82: 302-309.

and

R E Krupp (1994) Phase relations and phase transformations between the
low-temperature iron sulfides mackinawite, greigite, and smithite. Eur J
Mineralogy 6: 265-278.

Greigite has the inverse spinel structure, with Fe3+ occupying 100% of the
8(a) sites and 50% (along with 50% Fe2+) of the 16(d) sites. a = 9.876. The
sulfur positional parameter is 0.3755 (in first orientation of space group
in international tables, subtract 1/8 for alternative origin). Structure
given in:

Structure Reports 29, 63 (Skinner et al., 1964)

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