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.

Autor: Solodovnikov SF; Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation., Solodovnikova ZA; Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation., Zolotova ES; Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation., Kadyrova YM; Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Buryat Republic 670047, Russian Federation., Savina AA; Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Buryat Republic 670047, Russian Federation., Stefanovich SY; Department of Chemistry, Moscow State University, Moscow 119899, Russian Federation., Khaikina EG; Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Buryat Republic 670047, Russian Federation.
Jazyk: angličtina
Zdroj: Acta crystallographica. Section C, Structural chemistry [Acta Crystallogr C Struct Chem] 2017 Nov 01; Vol. 73 (Pt 11), pp. 946-952. Date of Electronic Publication: 2017 Oct 17.
DOI: 10.1107/S205322961701378X
Abstrakt: 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-43d, 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-42d (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 MZn 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.
Databáze: MEDLINE
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