Syntheses, crystal structures and vibrational properties of Rb4Si4S10 and Rb4Si4Se10

Rb2CdSi4S10: novel [Si4S10] T2-supertetrahedra-contained infrared nonlinear optical material with large band gap

“…To date, the [Si 4 S 10 ] T2-ST unit was observed in Na 4 Si 4 S 10 , Rb 4 Si 4 S 10 , and the title compound Rb 2 CdSi 4 S 10 . Nevertheless, the Na 4 Si 4 S 10 and Rb 4 Si 4 S 10 crystallize in the centrosymmetric space group ( Cmcm and C 2/ c ), 47,48 without SHG response. Hence, Rb 2 CdSi 4 S 10 was the first Si-rich sulfide IR-NLO material with the [Si 4 S 10 ] T2-ST. 49,50 Furthermore, the [Si 4 S 10 ] motifs formed were further connected with the [CdS 4 ] tetrahedra to construct a [CdSi 16 S 40 ] three-dimensional (3D) framework (Fig.…”

“…However, there are rare examples of [Si 4 S 10 ] T2-ST applied for the regulation of the E g of IR-NLO materials due to the experimental challenges in the synthesis of Si-rich (the molar ratio N = M Si /M total cations  100% Z 50%, where M represents the atomic molar number in the compound) metal sulfides. 47,48 From the previous discussion, the [Si 4 S 10 ] T2-ST unit was tried to introduce into the A I -B II -C IV -Q VI system, where alkali metal and sulfur atoms were chosen for the A and D sites (beneficial for obtaining a large E g ), and the IIB group element with d 10 electrons was selected for the B site (to increase the probability of a noncentrosymmetric (NC) compound, and provide the SHG effect). To avoid the decomposition of the Sirich sulfide at high temperatures, the flux method based on metal-chloride/sulfide with a low melting point was applied.…”

“…However, there are rare examples of [Si 4 S 10 ] T2-ST applied for the regulation of the E g of IR-NLO materials due to the experimental challenges in the synthesis of Si-rich (the molar ratio N = M Si / M total cations × 100% ≥ 50%, where M represents the atomic molar number in the compound) metal sulfides. 47,48…”

Sulfur speciation and network structural changes in sodium silicate glasses: Constraints from NMR and Raman spectroscopy

“…Reduced sulfur species that yield strong Raman bands near these positions include those containing the Si-S and S-S linkages (see Table 4). The Si-S stretching modes of crystalline SiS 2 and Rb 4 Si 4 S 10 , for example, are known to produce strong Raman bands near 430 and 368 cm Ϫ1 , respectively (e.g., Tenhover et al, 1983;Köster et al, 2002; also see Table 4). However, as described in section 3.2, our 29 Si-NMR spectra revealed no peaks attributable to SiO 4-n S n (n Ͼ 0) groups in any of the glasses synthesized from Na 2 O · xSiO 2 plus Na 2 SO 4 , Na 2 SO 3 , Na 2 S 2 O 3 and native sulfur.…”

“…b Reference: (1)Meyer et al (1980); (2)Konijnendijk and Buster (1977); (3)Brown and Ross (1972); (4)Degen and Newman (1993); (5)Holzer et al (1969); (6)Chivers and Lau (1982); (7)Janz et al (1976b); (8)Janz et al (1976a); (9)Tenhover et al (1983); (10)Köster et al (2002).…”