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Cs 3 LiZn 2 (WO 4 ) 4 and Rb 3 Li 2 Ga(MoO 4 ) 4 : different filled derivatives of the cation‐deficient Cs 6 Zn 5 (MoO 4 ) 8 structure
Author(s) -
Solodovnikov Sergey F.,
Solodovnikova Zoya A.,
Zolotova Evgeniya S.,
Kadyrova Yulia M.,
Savina Aleksandra A.,
Stefanovich Sergey Yu.,
Khaikina Elena G.
Publication year - 2017
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s205322961701378x
Subject(s) - isostructural , crystallography , chemistry , octahedron , dilithium , lithium (medication) , rubidium , crystal structure , tetragonal crystal system , space group , ion , stereochemistry , inorganic chemistry , x ray crystallography , potassium , deprotonation , physics , organic chemistry , medicine , diffraction , optics , endocrinology
Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs 3 LiZn 2 (WO 4 ) 4 , and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb 3 Li 2 Ga(MoO 4 ) 4 , belong to the structural family of Cs 6 Zn 5 (MoO 4 ) 8 (space group I 3 d , Z = 4), with a partially incomplete (Zn 5/6 □ 1/6 ) position. In Cs 3 LiZn 2 (WO 4 ) 4 , this position is fully statistically occupied by (Zn 2/3 Li 1/3 ), and in Rb 3 Li 2 Ga(MoO 4 ) 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 Cs 6 Zn 5 (MoO 4 ) 8 , Cs 3 LiZn 2 (WO 4 ) 4 and isostructural A 3 LiZn 2 (MoO 4 ) 4 and Cs 3 LiCo 2 (MoO 4 ) 4 are divided into two sites in Rb 3 Li 2 Ga(MoO 4 ) 4 , as in other isostructural A 3 Li 2 R (MoO 4 ) 4 compounds ( AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO 4 and (Zn,Li)O 4 or LiO 4 , GaO 4 and MoO 4 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·7Al 2 O 3 and isotypic compounds. Comparison of isostructural Cs 3 M Zn 2 (MoO 4 ) 4 ( M = Li, Na, Ag) and Cs 6 Zn 5 (MoO 4 ) 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 Cs 6 Zn 5 (MoO 4 ) 8 structure, while filling of the cation vacancies by larger Na + or Ag + ions plays a destabilizing role. The series A 3 Li 2 R (MoO 4 ) 4 shows second harmonic generation effects compatible with that of β′‐Gd 2 (MoO 4 ) 3 and may be considered as nonlinear optical materials with a modest nonlinearity.