定义Definition
铍是原子序数为 4 的元素，符号 Be，是第二族最轻的元素。铍是钢灰色、轻而硬的金属，不与水反应。Be²⁺ 半径极小、极化能力强，所以铍的化合物共价性明显，BeO 和 Be(OH)₂ 是两性的，这些性质与第二族其他元素不同，而与铝相似（对角线关系）。
Beryllium is the element with atomic number 4 and symbol Be, the lightest group 2 element. It is a light, hard, steel-grey metal that does not react with water. The tiny, strongly polarising Be²⁺ ion gives its compounds marked covalent character, and BeO and Be(OH)₂ are amphoteric. In these ways beryllium differs from the rest of group 2 and resembles aluminium (a diagonal relationship).
元素数据Element data
| 原子序数Atomic number | 4 |
|---|---|
| 元素符号Symbol | Be |
| 相对原子质量Standard atomic weight | 9.0122 |
| 电子排布Electron configuration | [He] 2s² |
| 族 / 周期 / 区Group / period / block | 2 / 2 / s |
| 电负性（鲍林）Electronegativity (Pauling) | 1.57 |
| 常见氧化态Common oxidation states | +2 |
用途与毒性Uses and toxicity
铍对 X 射线透明度高，用作 X 射线管的窗口材料；铍铜合金坚韧且不产生火花。铍及其化合物的粉尘有毒，吸入可导致慢性铍病。
Beryllium is very transparent to X-rays and is used for X-ray tube windows; beryllium–copper alloys are tough and non-sparking. Dust of beryllium and its compounds is toxic, and inhaling it can cause chronic beryllium disease.
化学性质Chemical properties
与氢氧化钠溶液反应：Be + 2NaOH + 2H₂O → Na₂[Be(OH)₄] + H₂
With sodium hydroxide solution: Be + 2NaOH + 2H₂O → Na₂[Be(OH)₄] + H₂
年表Timeline
- 1798
沃克兰在绿柱石中发现铍的氧化物
Vauquelin discovers beryllium oxide in beryl