A refinement of the structure of S₃O₉

The ν3 and 2ν3 bands of 32S16O3, 32S18O3, 34S16O3, and 34S18O3

“…In the solid crystalline phase only trimers exists, as has been found by X-ray analysis [19][20][21]. These, as well as the spectroscopic studies, show that the trimer exists in a chair form possessing C 3v symmetry.…”

An alternative approach to rationalizing the structures of the cyclotrisilicates: Rb10[Si6O17], Cs8[Si6O16] and Na3Y[Si6O15] by viewing them in light of the extended Zintl–Klemm concept

“…Its interpretation is straightforward in terms of the Zintl-Klemm concept: the transfer takes place of six e -from K atoms to the three Si atoms, each Si atom accepting two electrons so being converted into Si 2À anions, which -being electronically equivalent to S atoms -also convert structurally into pseudo-É-S 3 molecules. Similarly, the structure of the anion [Si 3 O 9 ] 6À É-S 3 O 9 is coincident with that of the real S 3 O 9 molecule (Pascard & Pascard-Billy, 1965;McDonald & Cruickshank, 1967), as shown in Fig. 1(b).…”

Syntheses, crystal structures and vibrational spectra of KLn(SO4)2·H2O (Ln=La, Nd, Sm, Eu, Gd, Dy)

“…The difference in the coordination number of the Ln cation in both structures is due to a slight rotation of the sulphate ion (S1). Therefore, the Sm-O14 distance (2.86Å) is drastically shorter than Dy-O14 (3.54Å), which reduces the coordination number from nine (1) [22,23], SO 3 [24], K 2 S 2 O 7 [25] and hexagonal ice [26] only by 1.2% (1) and 0.1% (2).…”