Structure and bonding in third-row main group dicarbides C2X (X=K-Br)

Area of Science:

• Computational Chemistry
• Inorganic Chemistry
• Quantum Chemistry

Background:

• Understanding the molecular geometries and bonding of main group element compounds is crucial in inorganic chemistry.
• Third-row main group elements offer unique electronic properties that can lead to novel chemical structures and reactivity.

Purpose of the Study:

• To investigate the ground-state molecular structures of third-row main group dicarbides (C(2)X, where X ranges from K to Br).
• To rationalize the observed structural preferences based on electronic interactions.
• To explore the stability and bonding characteristics of these novel compounds.

Main Methods:

• Theoretical computational methods were employed to study the molecular structures.
• Energy decomposition analysis was utilized to understand the interactions between the third-row atom and the dicarbon unit.

Main Results:

• Potassium (K), calcium (Ca), and gallium (Ga) dicarbides favor C(2v)-symmetric (T-shape) ground states.
• Arsenic (As), selenium (Se), and bromine (Br) dicarbides exhibit linear or quasilinear ground states.
• Germanium (Ge) dicarbides present a very flat potential energy surface, with an L-shape structure appearing as the ground state.
• Dissociation energies into X + C(2) were found to be relatively high, indicating significant stability.

Conclusions:

• The study successfully predicted diverse molecular geometries for third-row main group dicarbides.
• The structural preferences (linear, T-shape, L-shape) are rationalized by the interplay of electronic interactions between the third-row atom and the dicarbon moiety.
• These findings provide valuable insights into the chemical bonding and structural diversity of main group organometallic compounds.