OD (order-disorder) character of the crystal structure of godlevskite Ni9 S8
Merlino, Stefano; Makovicky, Emil
European Journal of Mineralogy Volume 21 Number 4 (2009), p. 863 - 869
published: Aug 1, 2009
ArtNo. ESP147052104016, Price: 29.00 €
Godlevskite Ni9 S8 has been found to be an OD (order-disorder) structure consisting of two kinds of OD layers in strict alternation; these layers display stacking disorder. They have layer symmetries P (4)2 m and P 21 2(2), respectively (symmetry elements in parentheses are perpendicular to OD layers). Two structures with maximum degree of order (MDO polytypes), with space-group symmetries A 222 and I 4122, respectively, exist, together with more complex polytypes or disordered sequences. The OD character is in keeping with the frequent twinning of godlevskite.