Planar pentacoordinate silicon and germanium atoms.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Computational Chemistry

Background:

• Traditional chemical bonding models often struggle with unusual coordination numbers.
• The search for stable, non-carbon-based planar pentacoordinate species is an ongoing challenge.
• Previous studies on XMg5(2-) structures provided a foundation for exploring modifications.

Purpose of the Study:

• To design and identify novel stable planar pentacoordinate compounds.
• To investigate the electronic and structural properties of group 14 elements in unusual coordination environments.
• To apply the "localization" approach for stabilizing high-coordinate species.

Main Methods:

• Computational modeling and theoretical calculations were employed.
• The "localization" approach was utilized by substituting peripheral atoms.
• Analysis of electron distribution and bonding characteristics.

Main Results:

• The global minimum structures for XMg4Y- (X = Si, Ge; Y = In, Tl) and SiMg3In2 were identified.
• These structures feature a planar pentacoordinate atom from group 14 (Si or Ge).
• The "localization" approach successfully reduced repulsion and strengthened covalent X-Y bonds.

Conclusions:

• Stable planar pentacoordinate silicon and germanium species have been theoretically designed.
• The "localization" approach is effective in stabilizing unusual coordination geometries.
• These findings open new avenues for designing novel materials with unique electronic properties.