This review covers H–H bond cleavage of dihydrogen (H₂) mediated by structurally well-defined rare-earth metal (scandium, yttrium and lanthanides) complexes, and their applications in homogenous catalysis, such as catalytic hydrogenation of unsaturated organic molecules. Depending on the mechanism of the H–H bond cleavage, this review is organized in two parts: (1) σ-bond metathesis, and (2) non-σ-metathesis H₂ activation. The latter is a new trend in this research field and is the emphasis of this review. Converting H₂ into inorganic rare-earth polyhydride complexes, albeit their potential applications as hydrogen-storage materiel, is not in the scope of this review.

这篇综述涵盖了由结构明确的稀土金属（钪、钇和镧系元素）配合物介导的二氢 (H ₂ ) 的H-H 键断裂，以及它们在均相催化中的应用，例如不饱和有机分子的催化氢化。根据 H–H 键断裂的机制，本综述分为两部分：(1) σ-键复分解，和 (2) 非 σ-复分解 H ₂活化。后者是该研究领域的一个新趋势，也是本综述的重点。将 H ₂转化为无机稀土多氢化物配合物，尽管它们作为储氢材料的潜在应用，不在本次审查的范围内。