The Crystal Structure of Ni(6(+/-)x)Se5.

The Real (Incommensurate Interface Modulated) Structure of Ni6±xSe5

“…The mechanism for such solid solution, however, is still far from clear. Average structure re"nements (10,12) are largely consistent with the idea of a well-de"ned, essentially fully occupied chalcogen array into some of the various interstices of which are "tted the required number of Ni atoms (see Fig. 1).…”

“…The phase can, however, be stabilized to room temperature either via rapid quenching or appropriate chalcogenide substitution (8,9). The average structure of the phase has been reported to be orthorhombic Bmmb with cell dimensions a&3.4, b&17.1, and c&11.9 A > in the case of the selenide and a&3.3, b&16.4, and c&11.3 A > in the case of the sul"de (9,10,12). (The parent re#ections corresponding to this average structure unit cell are labeled G in what follows).…”