Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

直到最近，路易斯酸性离子液体（ILs）一词几乎与卤化金属离子液体（ILs）成为同义词，并着重于氯铝酸盐（III）系统。这篇综述的第一部分介绍了这些化合物开发的历史背景，各种卤代金属离子液体的形态，试图量化其路易斯酸度的方法以及最近的一些应用：在工业烷基化工艺中，在支持的系统（SILP / SCILLs）中以及在无机合成中。在过去的十年中，出现了一些有趣的卤代金属离子液体替代品，它们可分为两个小节：（1）仍然基于卤代金属离子种类的液体配位配合物（LCC），但价格较卤代金属离子液体便宜且种类更多， （2）具有主要路易斯酸阳离子基团的IL。