Computational study of tetrasilylcyclobutadiene dianion and its dilithium salt. 6e-6c Three-dimensional aromaticity

Non-planar cyclobutadiene and tetrasilylcyclobutadiene dianions form dicapped bis-lithium salts which may be considered as six-electron six-center three-dimensional aromatic systems. Silyl groups increase the aromaticity of the cyclobutadiene dianion.