Erbium oxide (Er²O³) nanoparticles are increasingly recognized for their unique optical, magnetic, and catalytic properties. This article provides a comprehensive review of the synthesis methods, physical and chemical properties, and diverse applications of Er²O³ nanoparticles. Additionally, it addresses challenges associated with their use and outlines future research directions. 1. Introduction 1.1. Overview of Erbium Oxide Nanoparticles...