# Crystal and Magnetic Structures in Layered, Transition Metal Dihalides and Trihalides

## TL;DR

This paper reviews the crystallographic and magnetic properties of layered transition metal dihalides and trihalides, emphasizing their potential for low-dimensional physics and magnetic functionalities in two-dimensional materials.

## Contribution

It provides a comprehensive overview of the structures and magnetic behaviors of MX2 and MX3 compounds with layered architectures, highlighting their relevance for 2D material research.

## Key findings

- Layered structures enable cleavability into thin or monolayer crystals.
- Partially filled d-shell transition metals induce magnetic order.
- Crystallographic properties correlate with magnetic behaviors.

## Abstract

Materials composed of two dimensional layers bonded to one another through weak van der Waals interactions often exhibit strongly anisotropic behaviors and can be cleaved into very thin specimens and sometimes into monolayer crystals. Interest in such materials is driven by the study of low dimensional physics and the design of functional heterostructures. Binary compounds with the compositions MX2 and MX3 where M is a metal cation and X is a halogen anion often form such structures. Magnetism can be incorporated by choosing a transition metal with a partially filled d-shell for M, enabling ferroic responses for enhanced functionality. Here a brief overview of binary transition metal dihalides and trihalides is given, summarizing their crystallographic properties and long-range-ordered magnetic structures, focusing on those materials with layered crystal structures and partially filled d-shells required for combining low dimensionality and cleavability with magnetism.