The puzzling structure of bornite at low temperature

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Marco E. Ciriotti
Messaggi: 24596
Iscritto il: ven 25 giu, 2004 11:31
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The puzzling structure of bornite at low temperature

Messaggio da Marco E. Ciriotti » mar 14 ago, 2018 8:41

Prossima pubblicazione.

Referenza:
▪ Martinelli, A., Lepore, G.O., Bernardini, F., Giaccherini, A., Di Benedetto, F. (2018): The puzzling structure of Cu5FeS4 (bornite) at low temperature. Acta Crystallographica, B74, (in press).

Synopsis:
Several studies have focused on the positions of cations in bornite; however there is still a lack of definitive proof on the ordering of iron. Comparison between high-resolution diffraction data and EXAFS strongly suggests that the preferred location of iron is on two specific sites. Moreover, the high-resolution X-ray powder diffraction revealed that a low-temperature first transition occurs towards a even more puzzling structure, studied on the basis of the room-temperature structure.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 24596
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: The puzzling structure of bornite at low temperature

Messaggio da Marco E. Ciriotti » mer 29 ago, 2018 12:37

Referenza:
▪ Martinelli, A., Lepore, G.O., Bernardini, F., Giaccherini, A., Di Benedetto, F. (2018): The puzzling structure of Cu5FeS4 (bornite) at low temperature. Acta Crystallographica, B74, (in press).

Abstract
The crystal structure of Cu5FeS4 (bornite) has been investigated using synchrotron X‐ray powder diffraction at temperatures between 10 and 275 K. Diffraction data confirm that bornite crystallizes in the orthorhombic space group Pbca at 275 K. The unit‐cell volume decreases continuously on cooling, but undergoes an abrupt contraction below ∼65 K, where a first‐order PbcaPca21 structural transition takes place. The primary active mode yielding the observed ordered structure corresponds to the irreducible representation Γ2−, with wavevector (0,0,0). Pair distribution function analysis shows strong discrepancies between the local and the average structure. The average Fe—S bond length obtained through the EXAFS local probe is consistent with the values independently provided by X‐ray powder diffraction data, strongly supporting the preferred location of Fe.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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