Polymeric alkali fullerides are stable in air

TL;DR

This study demonstrates that certain polymeric alkali fullerides, specifically RbC$_{60}$ and KC$_{60}$, are stable in air, unlike other fullerides, which could enable their use as protective layers for superconducting materials.

Contribution

The paper provides experimental evidence of air stability in RbC$_{60}$ and KC$_{60}$, highlighting their potential for practical applications.

Findings

RbC$_{60}$ and KC$_{60}$ are stable in air.

Rb$_{6}$C$_{60}$ decomposes rapidly in air.

Polymeric alkali fullerides decompose above 100°C, transforming into C$_{60}$ and byproducts.

Abstract

Infrared transmission, electron spin resonance, and X-ray diffraction measurements show unambiguously that RbC$_{60}$ and KC$_{60}$ are stable in air, in contrast to Rb$_{6}$C$_{60}$ which decomposes rapidly upon exposure. The specimens studied transform into pure C$_{60}$ and other byproducts when heated above $100\dd $C, approximately the temperature of the orthorhombic-fcc phase transition. The stability of these compounds raises the possibility of applying them as protective layers for the superconducting fullerides.