ined   *S* = 0.00                            *w* = 0/\[σ^0^(*F*~o~^0^) + (0.0000*P*)^0^ + 0.0000*P*\] where *P* = (*F*~o~^0^ + 0*F*~c~^0^)/0   0000 reflections                      (Δ/σ)~max~ = 0.000   000 parameters                        Δρ~max~ = 0.00 e Å^−0^   0 restraints                          Δρ~min~ = −0.00 e Å^−0^   ------------------------------------- -------------------------------------------------------------------------------------------------  Special details {#specialdetails} ===============    ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------   Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 0000) operating at 000.0 (0) K.   Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.   Refinement. Refinement of F^0^ against ALL reflections. The weighted 