An experimental study on the preparation of tochilinite-originated intercalation compounds comprised of Fe1−xS host layers and various kinds of guest layers

Hydrothermal preparation of analogous matrix minerals of CM carbonaceous chondrites from metal alloy particles

“…Thus, the lattice parameters of the sulfide layer of the tochilinite nanotubes generally agree with those of normal Fe 1−x S (3.7 Å) (Organova et al, 1974;Peng et al, 2009), and the lattice parameters of the hydroxide layer of them do not have large difference with those of pure Fe(OH) 2 (a = b = 3.3 Å (trigonal)) (Lutz et al, 1994) and Mg(OH) 2 (a = b = 3.1 Å (trigonal)) (JCPDS card No.…”

“…A5 and Table A4 in the Appendix) indicated that the chemical composition of tochilinite have the following features: (a) 0.1 < Al/S atomic ratio < 0.2; (b) 0.23 < Mg/(Mg + Fe) atomic ratio < 0.87; (c) Si can be a minor component of tochilinite; (d) 0.8 < [(Mg, Al, Fe)(OH) 2 ]/(Fe 0.8 S) ratio < 1.5, larger than that (0.8-0.9) of terrestrial tochilinite (supposing that the sulfide layer of tochilinite has an ideal composition of Fe 0.8 S and the hydroxide layer has an ideal composition of (Mg, Al, Fe)(OH) 2 ) (Organova et al, 1974;Zolensky and Mackinnon, 1986;Peng et al, 2009).…”

“…In addition, the successful preparation of tochilinite and TCI may, to some extent, also show that Harder's viewpoint is correct, but the structures of tochilinite and TCI indicate that the Fe(OH) 2 or Fe(OH) 2 -like layers can also be stabilized by mackinawite-like Fe 1−x S layers in aqueous solution (Kakos et al, 1994;Kozerenko et al, 1996Kozerenko et al, , 2001Peng et al, 2007Peng et al, , 2009). …”

“…Contrary to the above simulated hydrothermal experiments, the successful syntheses of tochilinite and TCI have been carried out in strictly O 2 -free and reducing environment (Kakos et al, 1994;Kozerenko et al, 1996Kozerenko et al, , 2001Peng et al, 2007Peng et al, , 2009. Theoretical study on tochilinite indicated that tochilinite must be prepared in a reducing environment (log(oxygen fugacity) or log( f O 2 (g) ) < −85 or Eh < −0.45 V at standard temperature and pressure (STP, 25 • C and 10 5 Pa); Zolensky, 1984;Browning and Bourcier, 1996).…”

“…A typical feature of these minerals like tochilinite, TCI and cronstedtite, is that they all contain Fe(OH) 2 or Fe(OH) 2 -like layers (e.g. in the structure of cronstedtite) (Organova et al, 1974;Mackinnon and Zolensky, 1984;Peng et al, 2009;Pignatelli et al, 2013). Of course, the octahedrally coordinated iron in such layers can be replaced by other cations such as Mg 2+ , Fe 3+ and Al 3+ .…”