“…The normal at the planes Si1, N1, Si2A, N2A (or N2, Si2, N1A, Si1A) and at N2, Si1, N2A, Si1 enclose an angle of 120.2° and the Si–N bond lengths in 1 are in the expected range (171–173 pm). For example the corresponding values in N(SiMe 3 ) 3 , N(SiH 3 ) 3 and HNMe(SiMe 3 ) are 175.5 29, 172.9 20 and 172.0 pm 30, whereas in the cyclic compounds [ R 2 SiN R ′] 4 with R = Me, R ′ = H 172.0 (bowl) and 173.0 (chair) 28, R = R ′ = Me 173.0 (bowl) 31 and R = i Pr, R ′ = H 171.4 pm (bowl) 32 were found. The significant shortening of the Si–N bond lengths in comparison with the sum of the covalent radii (191 pm 33) is typical of aminosilanes 34.…”