 and goodness of fit *S* are based on *F*^0^, conventional *R*-factors *R* are based on *F*, with *F* set to zero for negative *F*^0^. The threshold expression of *F*^0^ \> σ(*F*^0^) is used only for calculating *R*-factors(gt) etc. and is not relevant to the choice of reflections for refinement. *R*-factors based on *F*^0^ are statistically about twice as large as those based on *F*, and *R*- factors based on ALL data will be even larger.   -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------  Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^0^) {#tablewrapcoords} ==================================================================================================    ----- -------------- ------------- --------------- -------------------- --         *x*            *y*           *z*             *U*~iso~\*/*U*~eq~      I0    