nonmetal atom silicon atom 14Si 28.08550 A carbon group element atom that has formula Si. CAS:7440-21-3 CHEBI:26676 CHEBI:27573 CHEBI:9140 InChI=1S/Si KEGG:C06263 Si Silicon Silizium WebElements:Si XUIMIQQOPSSXEZ-UHFFFAOYSA-N [Si] chebi_ontology silicio silicium silicon silicon carbon group element atom