ChemInform Abstract: Phase Relations in the Na₂MoO₄—Cs₂MoO₄ and Na₂MoO₄—Cs₂MoO₄ —ZnMoO₄ Systems, Crystal Structures of Cs₃Na(MoO₄)₂ and Cs₃NaZn₂(MoO₄)₄.

Abstract

Systems, Crystal Structures of Cs 3Na(MoO4)2 and Cs3NaZn2(MoO4)4. -In view of incomplete data, the binary systems Na 2MoO4-Cs2MoO4 and Na2MoO4-ZnMoO4 bounding the Na2MoO4-Cs2MoO4-ZnMoO4 phase system are reinvestigated by annealing appropriate amounts of monomolybdates (420-700 C, 50-200 h). The new intermediate compound Cs 3Na(MoO4)2 is found to melt incongruently at 510 C. It crystallizes with the glaserite type structure (triclinic, space group P3m1, Z = 1; powder XRD). The sub solidus phase relations of the system Na 2MoO4-Cs2MoO4-ZnMoO4 are studied at 420 C. The filling of vacancies in the Cs 6Zn5(MoO4)8 structure results in the continuous solid solution Cs 6Zn5-x1-xNa2x(MoO4)8 (x = 0-1). With increasing x, the cubic lattice parameters increase linearly while the melting point decreases indicating the destabilization of the Cs 6Zn5(MoO4)8 structure by progressive Na + insertion. In the structure of Cs 3NaZn2 (MoO4)4 (cubic, space group I43d, Z = 2), MoO4 and (Zn2/3Na1/3)O4 tetrahedra share corners to form an open 3D framework with Cs disordered around the centers of the cuboctahedral cavities. -(ZOLOTOVA, E. S.; SOLODOVNIKOVA, Z. A.; YUDIN*, V. N.; SOLODOVNIKOV, S. F.; KHAIKINA, E. G.; BASOVICH, O. M.; KOROLKOV, I. V.; FILATOVA, I. Y.; J. Solid State Chem. 233 (2016) 23-29, http://dx.

Synthesis, Structure, and Conductivity of Alluaudite‐Related Phases in the Na2MoO4–Cs2MoO4–CoMoO4 System

“…The above‐mentioned abundance of the alluaudite‐type among double molybdates of sodium and bivalent metals allows us hoping to continue the series Na 25 Cs 8 R 5 (MoO 4 ) 24 ( R = Fe, Sc, In) in the systems Na 2 MoO 4 –Cs 2 MoO 4 – M MoO 4 ( M = Mg, Mn, Co, Ni, Cu, Zn, Cd). However, our study of the system Na 2 MoO 4 –Cs 2 MoO 4 –ZnMoO 4 showed no similar phase and predominance of the solid solution Cs 6 Zn 5‐ x ⬜ 1‐ x Na 2 x (MoO 4 ) 8 (0 ≤ x ≤ 1) with the Cs 6 Zn 5 (MoO 4 ) 8 structure (sp. gr.…”

“…The subsolidus phase relations of the system Na 2 MoO 4 –Cs 2 MoO 4 –CoMoO 4 were determined using the methods of intersecting joins and “significant points” elaborated for the ternary systems with binary compounds in the boundary systems and described in in detail. The samples corresponding to eight selected significant points[34b] sufficient for inspecting phase compositions of all joins of the Na 2 MoO 4 –Cs 2 MoO 4 –CoMoO 4 system, were annealed at 480 °C for 200 h with daily intermittent grindings.…”

“…This work continues our research and deals with phase formation, synthesis, crystal structures and ionic conductivity of alluaudite‐related phases in the system Na 2 MoO 4 –Cs 2 MoO 4 –CoMoO 4 . Upon studying the phase formation, we used the literature data[3b], [3e], and results of our investigations[3a], , of the boundary systems. According to these data, there are five incongruently melting double molybdates: Cs 3 Na(MoO 4 ) 2 of the glaserite K 3 Na(SO 4 ) 2 type, Cs 2 Co 2 (MoO 4 ) 3 of the langbeinite, K 2 Mg 2 (SO 4 ) 3 , type, alluaudite‐type Na 4–2 x Co 1+ x (MoO 4 ) 3 (0.05 ≤ x ≤ 0.30 at 600 °C), Na 2–2 y Co 2+ y (MoO 4 ) 3 (0.05 ≤ y ≤ 0.25 at 600 °C) of the lyonsite, α‐Cu 3 Fe 4 (VO 4 ) 6 , type and Na 2–2z Co 2+z (MoO 4 ) 3 (0.10 ≤ z ≤ 0.40 at 700 °C) isostructural to Na 2 Mg 5 (MoO 4 ) 6 [16a] and howardevansite NaCuFe 2 (VO 4 ) 3 .…”