Mercury is a volatile element whose synthesis mainly involves the s-过程 (slow neutron capture) in asymptotic giant branch (AGB) stars. It belongs to the so-called "moderately volatile" elements, meaning it condenses at relatively low temperatures during planet formation. This volatility partly explains its distribution in the solar system: it is significantly depleted in terrestrial planets (such as Earth) compared to solar abundances, as much of it remained gaseous during accretion and was blown away by the young Sun.
汞在宇宙中的丰度约为氢原子数的1.5×10⁻¹¹倍，与硒和溴的含量相当。在地球上，地壳中汞的含量相对稀少（约0.08 ppm）。它在其他天体上的存在令人着迷：水星（仅名称巧合）的外逸层中含有微量原子态汞，可能是微陨石撞击其表面释放的。彗星和一些富含冰的小行星也可能以有机汞化合物或硫化物的形式含有汞。
On Earth, mercury follows a complex cycle involving the atmosphere, oceans, crust, and biosphere. Its elemental form (Hg⁰) is volatile and can travel long distances in the atmosphere before being oxidized and deposited. This 全球大气输送 explains why mercury pollution is a worldwide problem, affecting even the most remote regions such as the Arctic. The study of ice cores allows us to trace the history of mercury emissions linked to human activities (mining, coal combustion) over millennia.
Mercury anomalies have been identified in marine sediments at the boundary of several mass extinction events (Permian-Triassic, Triassic-Jurassic, Cretaceous-Paleogene). These peaks could be linked to 大规模的火山活动 (traps) that released enormous amounts of volatile mercury into the atmosphere, contributing to the poisoning of ecosystems. Thus, mercury also serves as a geological tracer of major environmental upheavals of the past.
The chemical symbol Hg comes from the Latin "汞", itself derived from the ancient Greek 水银 (hýdōr árgyros), meaning "liquid silver". This name perfectly describes its appearance: a metal as shiny as silver, but liquid. The French name "mercure" comes from the Roman god Mercury (Hermes to the Greeks), the swift messenger of the gods, perhaps in reference to the mobility and volatility of the liquid metal.
天然汞（以朱砂HgS的形式存在）自古便为人所知。中国人和埃及人将其用作朱红色颜料及药材（常引发灾难性后果）。炼金术士视汞为根本元素，与硫磺、盐并列为构成物质的三大基本原理。他们相信汞是点石成金的关键——其溶解黄金（形成汞齐）的能力，以及挥发后完整冷凝的特性，令世人着迷，更催生了诸多神秘理论。
18世纪，水银在温度测量（华氏与摄氏温度计）和气压测量（托里拆利实验，1643年通过水银柱证明大气压存在）的发展中发挥了关键作用。其有毒化合物如甘汞（Hg₂Cl₂）和升汞（HgCl₂）的发现，也标志着制药化学与工业化学的开端。
The main source of mercury is 朱砂 (mercury(II) sulfide, HgS), a scarlet red ore. Major deposits have been exploited in Almadén (Spain, the largest historical mine), Idrija (Slovenia), and Monte Amiata (Italy). Today, primary mining production has significantly decreased due to toxicity and environmental restrictions. 中国 and 吉尔吉斯斯坦 are among the last significant producers.
Most of the mercury circulating today comes from 回收利用 or is a 副产品 of other activities:
由于其毒性，汞的贸易受到《水俣公约》（2013年）的严格管制。
汞（符号Hg，原子序数80）是第六周期的过渡金属，位于元素周期表第12族，与锌和镉同族。其原子含有80个质子，通常有122个中子（对应稳定同位素\(^{202}\mathrm{Hg}\)），以及80个电子，电子排布为[Xe] 4f¹⁴ 5d¹⁰ 6s²。这种具有完整d¹⁰壳层和完整s²壳层的排布与稀有气体相似，使其金属形态反应活性低，且熔点较低。
Mercury is the 唯一在常温常压下呈液态的金属. It is a dense, silvery-white, mobile liquid that easily divides into spherical droplets.
在固态下，汞具有延展性和可塑性，并以菱面体结构结晶。
Mercury freezes at -38.8290 摄氏度 (234.321 K) and boils at 356.73 °C (629.88 K). Its wide liquid temperature range (nearly 400°C) and its linear expansion made it successful in measuring instruments.
汞是一种相对惰性的金属。它不与非氧化性酸（稀盐酸、稀硫酸）反应，但可溶于硝酸和王水。在室温下，汞能抵抗空气氧化，但在臭氧存在下会缓慢形成灰色氧化膜。它能与卤素、硫及金属反应生成汞齐。
State at 20°C: Liquid.
Melting point: 234.321 K (-38.8290 °C).
Boiling point: 629.88 K (356.73 °C).
Density: 13.534 g/cm³.
Electronic configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s².
Main oxidation states: +1 and +2.
| 同位素 / 符号 | 质子（Z） | 中子（N） | 原子质量（u） | 天然丰度 | 半衰期/稳定性 | 衰变/备注 |
|---|---|---|---|---|---|---|
| 汞-196 — \(^{196}\mathrm{Hg}\) | 80 | 116 | 195.96583 u | ≈ 0.15% | 稳定的 | 稀有稳定同位素。 |
| 汞-198 — \(^{198}\mathrm{Hg}\) | 80 | 118 | 197.966769 u | ≈ 9.97% | 稳定的 | 稳定同位素。 |
| 汞-199 — \(^{199}\mathrm{Hg}\) | 80 | 119 | 198.968280 u | ≈ 16.87% | 稳定 | 核自旋I=1/2的稳定同位素，用于\(^{199}\mathrm{Hg}\)核磁共振波谱分析。 |
| 汞-200 — \(^{200}\mathrm{Hg}\) | 80 | 120 | 199.968326 u | ≈ 23.10% | 稳定的 | 稳定同位素。 |
| 汞-201 — \(^{201}\mathrm{Hg}\) | 80 | 121 | 200.970302 u | ≈ 13.18% | 稳定的 | 稳定同位素。 |
| 汞-202 — \(^{202}\mathrm{Hg}\) | 80 | 122 | 201.970643 u | ≈ 29.86% | 稳定 | 最丰富的稳定同位素。 |
| 汞-204 — \(^{204}\mathrm{Hg}\) | 80 | 124 | 203.973494 u | ≈ 6.87% | 稳定 | 稳定同位素。 |
注意：:
Electron shells: 电子如何围绕原子核组织.
汞有80个电子，分布在六个电子壳层中。其电子排布为[Xe] 4f¹⁴ 5d¹⁰ 6s²，其中5d壳层完全填满（10个电子），6s壳层也完全填满（2个电子），类似于稀有气体的构型。这也可以表示为：K(2) L(8) M(18) N(32) O(18) P(2)，或完整写法：1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s²。
K壳层（n=1）: 2 electrons (1s²).
L壳层（n=2）: 8 electrons (2s² 2p⁶).
M层（n=3）: 18 electrons (3s² 3p⁶ 3d¹⁰).
N壳层（n=4）: 32 electrons (4s² 4p⁶ 4d¹⁰ 4f¹⁴).
O壳层 (n=5): 18 electrons (5s² 5p⁶ 5d¹⁰).
P壳层（n=6）: 2 electrons (6s²).
Mercury has 2 价电子 (6s²). However, due to the inert pair effect (particular stability of the 6s² electron pair), mercury exhibits a particular chemistry with two stable oxidation states: +1 and +2.
金属汞（Hg⁰）相对不活泼，这是因为液态中Hg-Hg键的强度较高，且将6s电子激发到更高能级需要较高能量。
金属汞在室温下不会在空气中氧化。当缓慢加热至沸点时，最终会形成红色的氧化汞(II)（HgO）：2Hg + O₂ → 2HgO。这种氧化物在400°C以上会分解回汞和氧气。在臭氧存在下，表面会形成一层灰色的氧化膜。
注意：:
This is a characteristic property: mercury dissolves many other metals (gold, silver, tin, zinc, sodium) to form 汞齐, which are alloys in liquid or pasty state. The gold-mercury amalgam has been widely used in artisanal gold extraction (garimpos). The silver-tin-mercury amalgam was the basis of dental "fillings". Sodium or potassium amalgams are used as powerful reducing agents in organic chemistry.
The toxicity of mercury depends strongly on its 化学形式:
In case of metallic mercury spillage, it is necessary to 彻底通风, avoid walking on it (to prevent spreading droplets), and use a specific trap (syringe, pipette, sulfur powder) to collect it. Never use a vacuum cleaner (it vaporizes and disperses mercury). Exposure requires urgent medical consultation. Treatment of acute poisoning may use 螯合剂 such as DMSA (dimercaptosuccinic acid) or DMPS, which bind to mercury and promote its urinary excretion.
汞是一种持久性污染物，遵循复杂的循环过程：
Mercury pollution affects wildlife (reduced reproduction in fish-eating birds, neurological disorders in marine mammals). For humans, the main route of exposure is the 食用受污染鱼类. The most at-risk populations are coastal communities, indigenous peoples (Inuit), and pregnant women (methylmercury crosses the placenta and harms fetal neurological development).
The 水俣公约, adopted in 2013 and entered into force in 2017, is an international treaty aimed at protecting human health and the environment. It requires:
Given the toxicity and persistence of mercury, it is imperative to 恢复并隔离 it from the biosphere permanently. Mercury cannot be "destroyed" (the atoms persist), but it can be stabilized in less dangerous forms.
The main challenges are the 逐步淘汰 of the last uses (certain chemical processes, certain lamps), the 污染场地修复 (former factories, mines), and the management of 流通产品中的汞 (millions of thermometers and dental amalgams). Research continues on biological decontamination methods (phytoremediation) and on non-toxic alternatives in all areas where mercury was historically used.
原子的各种形态：从古代直觉到量子力学 
