An asymmetrically substituted borazine

The B₃N₃ ring in the title compound, 1,3,5‐tri‐tert‐butyl‐2,4‐difluoro‐6‐phenyl­cyclo­triborazane, PhF₂B₃N₃^tBu₃] or C₁₈H₃₂B₃F₂N₃, an asymmetrically substituted borazine, is distorted from planarity. The molecule resides on a twofold axis. The N atoms of the N—B(Ph)—N group lie on opposite sides of the least‐squares plane formed by the four remaining ring atoms, due to steric accommodation of the tert‐butyl groups, a conformation not previously observed for a borazine. The B—N bond lengths are in the range 1.4283 (14)–1.4493 (12) Å, due to the F substituents residing on two of the B atoms, which also produce a large deviation from 120° in one of the B—N—B angles ca 113.6 (1)°]. The phenyl group is twisted with respect to the B₃N₃ ring, the interplanar angle being 62.87 (5)°.