AbstractThe existence and gas phase stability of silicon analogues of three natural amino acids (i.e., silicon glycine, silicon alanine, and silicon valine) belonging to the novel class of compounds termed silicon amino acids (SiAA) are investigated theoretically on the basis of ab initio QCISD/aug‐cc‐pVTZ and MP2/aug‐cc‐pVTZ calculations. All molecules studied (in their gas phase canonical forms) are structurally comparable to their proteinogenic counterparts (i.e., glycine, l‐alanine, and l‐valine) and capable of forming several structural isomers as such. These higher energy isomers are characterized by small relative energies (not exceeding 4 kcal mol−1). The simulated IR spectra of the Si‐Gly, Si‐Ala, and Si‐Val global minima are also presented and discussed.