So PI bonds have electron density both above and below the bond axis, but they actually have a nodal plane at this z, this bond axis here.
键在键轴之上，和之下都有电子密度，但它们在z方向有节面，这是键轴的地方。
2
Square of the Planck constant times pi mass of the electron.
普朗克常量的平方,乘以π再乘电子的质量。
3
The framing negotiates still definitely specified, will construct a PIelectron product in the HengYang among them capacity fabrication and generalize site.