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. A colorless crystal (plate, approximate dimensions 0.20 × 0.10 × 0.05 mm3) was placed onto the tip of a MiTeGen pin and mounted on a Bruker Venture D8 diffractometer equipped with a Photon II detector at 100.0 K. The data collection was carried out using Mo Kα radiation (λ = 0.71073 Å, graphite monochromator) with a frame time of 0.5 seconds and a detector distance of 50 mm. Complete data to a resolution of 0.77 Å with a redundancy of 4 were collected. The frames were integrated with the Bruker software package SAINT using a narrow-frame algorithm (Bruker, 2016) to a resolution of 0.77 Å.The space group Pbcn was determined based on intensity statistics and systematic absences. The structure was solved using SHELXT (Sheldrick, 2015) and refined using full-matrix least-squares on F2with the OLEX2 suite (Dolomanov et al., 2009). An intrinsic phasing solution was calculated, which provided most non-hydrogen atoms from the E-map. Full-matrix least squares / difference Fourier cycles were performed, which located the remaining non-hydrogen atoms. All non-hydrogen atoms were refined with anisotropic displacement parameters.