Mercuric (Hg²⁺) ions released from human activities, natural phenomena, and industrial sources are regarded as the global pollutant of world’s water. Hg²⁺ ions contaminated water has several adverse effects on human health and the environment even at low concentrations. Therefore, rapid and cost-effective method is urgently required for the detection of Hg²⁺ ions in water. Although, the current analytical methods applied for the detection of Hg²⁺ ions provide low detection limit, they are time consuming, require expensive equipment, and are not suitable for in-situ analysis. Metal nanoclusters (MNCs) consisting of several to ten metal atoms are important transition missing between single atoms and plasmonic metal nanoparticles. In addition, sub-nanometer sized MNCs possess unique electronic structures and the subsequent unusual optical, physical, and chemical properties. Because of these novel properties, MNCs as a promising material have attracted considerable attention for the construction of selective and sensitive sensors to monitor water quality. Hence this review is focused on recent advances on synthesis strategies, and optical and chemical properties of various MNCs including their applications to develop optical assay for Hg²⁺ ions in aqueous solutions.

人类活动、自然现象和工业源释放的汞（Hg ²⁺）离子被认为是世界水体的全球污染物。Hg ²⁺离子污染的水即使在低浓度下也会对人类健康和环境产生多种不利影响。因此，迫切需要一种快速、经济有效的方法来检测水中的Hg ²⁺离子。虽然，目前用于检测 Hg ^{2+的分析方法}离子检测限低，耗时长，需要昂贵的设备，不适合原位分析。由几个到十个金属原子组成的金属纳米团簇 (MNC) 是单个原子和等离子体金属纳米粒子之间缺失的重要过渡。此外，亚纳米尺寸的跨国公司拥有独特的电子结构和随后不寻常的光学、物理和化学特性。由于这些新颖的特性，跨国公司作为一种有前途的材料在构建选择性和灵敏的传感器以监测水质方面引起了相当大的关注。因此，本综述侧重于合成策略的最新进展，以及各种 MNC 的光学和化学性质，包括它们在开发 Hg ^{2+光学检测方面的应用}水溶液中的离子。