# Endohedral [Au@In10]9– Cluster: Synthesis and Characterization of Na3+x A 6–x In10Au (x = 0, 0.25; A = Rb, Cs)

## TL;DR

This paper reports the synthesis and characterization of two new compounds containing [Au@In10]9– clusters, highlighting their structural and electronic properties.

## Contribution

The paper introduces new Na-Rb-In-Au and Na-Cs-In-Au compounds with stable [Au@In10]9– clusters and confirms their salt-like Zintl-type nature.

## Key findings

- The alkali metal composition determines the structure, while the [Au@In10]9– cluster remains unchanged.
- Quantum calculations show a band gap at the Fermi level, indicating salt-like electronic behavior.
- Dissolution in liquid ammonia produces In2Au as a reaction product.

## Abstract

The synthesis and characterization of two new compounds
Na3Rb6In10Au and Na3.25Cs5.75In10Au are reported, which contain [Au@In10]9– clusters as anionic entities. Single-crystal
X-ray structure analysis shows that the alkali metal composition is
the key factor for structure formation, while the anionic entity remains
unchanged. The chemical composition was confirmed by SEM/EDS measurements,
and the given compositions of both compounds are fixed according to
the line compounds. Quantum chemical calculations for the compound
Na3Rb6In10Au were performed and show
a band gap at the Fermi level, classifying the materials as salt-like,
including endohedral [Au@In10]9–
Zintl-type clusters. Dissolution experiments in liquid ammonia
were carried out, revealing In2Au as the reaction product.