Threefold coordinated germanium in a GeO₂ melt

Area of Science:

• Material science
• Geochemistry
• Solid-state chemistry

Background:

• The local structure of germanium in GeO2 melt is a fundamental, debated topic.
• Prevailing view suggests germanium is coordinated by at least four oxygen atoms.
• Unexplained bands in Raman spectra challenge existing models of GeO2 melt structure.

Purpose of the Study:

• To investigate the local structure of germanium in GeO2 melt.
• To resolve the longstanding debate regarding germanium coordination in GeO2.
• To provide a new perspective on germanate chemistry.

Main Methods:

• In situ Raman spectroscopy was employed to analyze GeO2 melt.
• Density functional theory (DFT) computations were utilized for structural analysis.
• Computational electronic structure analysis elucidated bonding characteristics.

Main Results:

• A novel [GeOØ2]n chain structure was identified in GeO2 melt, where Ø represents bridging oxygen.
• In this structure, germanium is primarily coordinated by three oxygen atoms.
• A weak interaction was observed between germanium and neighboring non-bridging oxygen atoms.

Conclusions:

• The identified chain structure provides a resolution to the ongoing debate on GeO2 melt structure.
• The findings necessitate a revision of the prevailing viewpoint on germanium coordination.
• This study offers new insights into the fundamental aspects of germanate chemistry.