Phase Formation in the Li2MoO4–Rb2MoO4–Fe2(MoO4)3 System and Crystal Structure of a Novel Triple Molybdate LiRb2Fe(MoO4)3

  • a Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakh'yanova St. 6, Ulan-Ude, 670047, Buryat Republic, Russia

  • b Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Akad. Lavrent'ev Ave. 3, Novosibirsk, 630090, Russia

  • c Novosibirsk State University, Pirogov St. 2, Novosibirsk, 630090, Russia

  • d Buryat State University, Smolin St. 24a, Ulan-Ude, 670000, Buryat Republic, Russia


The Li2MoO4–Rb2MoO4–Fe2(MoO4)3 system study revealed a new compound LiRb2Fe(MoO4)3.

Its structure of a new type includes ribbons of FeO6 octahedra and MoO4 tetrahedra.

The ribbons are connected into a 3D framework via corner-sharing LiO4 tetrahedra.


X-ray investigation of solid state interaction of the components in the Li2MoO4–Rb2MoO4–Fe2(MoO4)3 system was carried out, and a subsolidus phase diagram of the said system was constructed. The subsystem Rb2MoO4–LiRbMoO4–RbFe(MoO4)2 was shown to be non-quasiternary. Formation of a novel triple molybdate LiRb2Fe(MoO4)3 was established, conditions of solid state synthesis and crystallization of the compound were found. Its crystal structure (orthorhombic, space group Pnma, Z=4, a=24.3956(6), b=5.8306(1), c=8.4368(2) Å) represents a new structure type and includes infinite two-row ribbons {[Fe(MoO4)3]3−} parallel to the b axis and composed of FeO6 octahedra, terminal Mo(3)O4 tetrahedra, and bridge Mo(1)O4 and Mo(2)O4 tetrahedra connecting two or three FeO6 octahedra. The ribbons are connected to form 3D framework via corner-sharing LiO4 tetrahedra. Rubidium cations are 11- and 13-coordinated and located in cavities of this heterogeneous polyhedral framework.

Graphical abstract

Exploring the Li2MoO4–Rb2MoO4–Fe2(MoO4)3 system showed its partial non-quasiternarity and revealed a new compound LiRb2Fe(MoO4)3 which was structurally studied.

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