boron

He said there should be an element under boron.

他认为在，硼的下面也有个元素。

So, we have beryllium in the first case here, it has four electrons, that's how we know it's beryllium, boron has five electrons.

那么我们将铍作为第一个例子，它有四个电子，这也是我们为什么能知道它是铍的原因，硼有五个电子。

Only small amounts of wurtzite boron nitride and lonsdaleite exist naturally or have been made in the lab so until now no one had realised their superior strength.

天然存在或者实验室制造的纤锌矿型氮化硼和朗斯代尔石数量很少，直到现在，也没有一个人发现它们令人吃惊的硬度。