There is another reason why you may not be able to see the animals.

VOA: special.2010.01.04

So, we need to fill our octet for selenium, so 1, 2, 3, 4.So, this is our Lewis structure here, hopefully you can see why it's not linear.

我们要填满硒原子的八配位，所以1，2，3，4。这就是Lewis结构，希望你们能看出来为什么它不是直线型的。

麻省理工公开课 - 化学原理课程节选