Cs3LiZn2(WO4)4 and Rb3Li2Ga(MoO4)4: different filled derivatives of the cation‐deficient Cs6Zn5(MoO4)8 structure. Issue 11 (17th October 2017)

• Record Type: Journal Article
• Authors: Solodovnikov, Sergey F.; Solodovnikova, Zoya A.; Zolotova, Evgeniya S.; Kadyrova, Yulia M.; Savina, Aleksandra A.; Stefanovich, Sergey Yu.; Khaikina, Elena G.
• Is Part Of: Acta crystallographica. Volume 73:Issue 11(2017)
• Page Start: 946
• Page End: 952
• Publication Date: 2017-10-17
• Subjects: triple tungstate -- triple molybdate -- tetrahedral framework -- filling vacancies -- crystal structure -- structural family -- crystal chemistry -- thermal stability -- second harmonic generation; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S205322961701378X
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : Cs3 LiZn2 (WO4 )4 and Rb3 Li2 Ga(MoO4 )4 represent two distinct series of filled derivatives of the cation‐deficient Cs6 Zn5 (MoO4 )8 structure with three‐dimensional tetrahedral frameworks related to that of mayenite 12CaO·7Al2 O3 . The series of tetragonal A 3 Li2 R (MoO4 )4 compounds exhibits second harmonic generation effects compatible with that of β′‐Gd2 (MoO4 )3 . Abstract : Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs3 LiZn2 (WO4 )4, and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb3 Li2 Ga(MoO4 )4, belong to the structural family of Cs6 Zn5 (MoO4 )8 (space group I 3 d, Z = 4), with a partially incomplete (Zn5/6 □1/6 ) position. In Cs3 LiZn2 (WO4 )4, this position is fully statistically occupied by (Zn2/3 Li1/3 ), and in Rb3 Li2 Ga(MoO4 )4, the 2Li + Ga atoms are completely ordered in two distinct sites of the space group I 2 d ( Z = 4). In the same way, the crystallographically equivalent A + cations ( A = Cs, Rb) in Cs6 Zn5 (MoO4 )8, Cs3 LiZn2 (WO4 )4 and isostructural A 3 LiZn2 (MoO4 )4 and Cs3 LiCo2 (MoO4 )4 are divided into two sites in Rb3 Li2 Ga(MoO4 )4, as in other isostructural A 3 Li2 R (MoO4 )4 compounds ( AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO4 and (Zn, Li)O4 or LiO4, GaO4 and MoO4 tetrahedra share corners to form open three‐dimensional frameworks with the caesium or rubidium ions occupying cuboctahedral cavities. The tetrahedral frameworks are related to that of mayenite 12CaO·7Al2 O3 and isotypic compounds. Comparison of isostructural Cs3 M Zn2 (MoO4 )4 ( M = Li, Na, Ag) and Cs6 Zn5 (MoO4 )8 shows a decrease of the cubic lattice parameter and an increase in thermal stability with the filling of the vacancies by Li + in the Zn position of the Cs6 Zn5 (MoO4 )8 structure, while filling of the cation vacancies by larger Na + or Ag + ions plays a destabilizing role. The series A 3 Li2 R (MoO4 )4 shows second harmonic generation effects compatible with that of β′‐Gd2 (MoO4 )3 and may be considered as nonlinear optical materials with a modest nonlinearity.