Nitrosonium tetrafluoridoborate, NOBF4

NOBF4 crystallizes in the baryte structure type with orthorhombic Pnma symmetry and exhibits cationic disorder.


Synthesis and crystallization
A sample of NOBF 4 suitable for single-crystal X-ray diffraction was obtained from a commercial source (Alfa Aesar, 98%). Crystals were placed onto a watch glass and covered with a protective layer of perfluorodecalin (ABCR, AB102850, 98%, cis and trans) inside an argon-filled glovebox (MBraun, H 2 O < 0.5 ppm). A suitable colorless crystal was selected under a polarizing microscope outside the glovebox, mounted on a MiTeGen Dual Thickness MicroLoop with the aid of Baysilone-Paste, and quickly transferred into a cold nitrogen stream of the X-ray diffractometer.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. The coordinates and anisotropic displacement parameters of the disordered atoms O1 and N1 sharing the same site were constrained to be equal (EXYZ, EADP) and their site occupancy factor set to 0.5.

Funding information
The author is grateful for research funding from the Jožef Stefan Institute Director's Fund, the Slovenian Research Agency (N1-0189, P1-0045), and the European Research Council (950625).

Figure 1
Expanded asymmetric unit of NOBF 4 with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
View of the packing in the unit cell of the NOBF 4 crystal structure. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.22 e Å −3 Δρ min = −0.28 e Å −3 Special details 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ.