单键

rú guǒ zhè lǐ yǒu gè dān jiàn nǐ jué de zhè shì jiàn hái shi jiàn

如果这里有个单键，你觉得这是sigma键还是π键？

So if we have a single bond here, would you consider that a sigma bond or a pi bond?

yuán zǐ de dān jiàn bàn jìng suí wēn dù shēng gāo ér zēng dà

原子的单键半径随温度升高而增大。

The single bond radius increases with the elevating temperature.