Tris(2‐pyridyl)­phosphine oxide: how C—H⃛O and C—H⃛N interactions can affect crystal packing efficiency

Tris(2‐pyridyl)­phosphine oxide, (I), C₁₅H₁₂N₃OP, is isomorphous with tris(2‐pyridyl)­phosphine. Because of a combination of C—H⋯O and C—H⋯N interactions, the crystal packing is denser in the title compound than in the related compounds tri­phenyl­phosphine oxide and tris(2‐pyridyl)­phosphine.