Synthesis and X-Ray Diffraction Study of Potassium, Rubidium, and Cesium Polytungstates with Defect Pyrochlore and Hexagonal Tungsten Bronze Structures.-X-ray studies on the phase formation in M 2 WO 4 -WO 3 systems (M: K, Rb, Cs) verify the formation ofCs 6 W 11 O 36 and the existence of M 4 W 11 O 35 and M 2 W 7 O 22 phases. M 2 W 3 O 10 and Cs 6 W 11 O 36 possess a pyrochlore type structure whilst the structure of M 4 W 11 O 35 and M 2 W 7 O 22 resembles hexagonal tungsten bronze. Appropriate conditions for the solid phase synthesis and crystallization of discrete polytungtates from the corresponding alkali carbonate M 2 CO 3 and WO 3 are established. -(SOLODOVNIKOV, S. F.; IVANNIKOVA, N. V.; SOLODOVNIKOVA, Z. A.; ZOLOTOVA, E. S.; Neorg.
A subsolidus triangulation of Li 2 MoO 4 -Rb 2 MoO 4 -MMoO 4 (M = Ca, Sr, Pb, Ba) systems is performed. The RbLiMoO 4 -Rb 2 M(MoO 4 ) 2 (M = Pb, Ba) joins, where 11 mol.% long Rb 2 M(MoO 4 ) 2 -based solid solutions are found, are studied in most detail. Ternary molybdates do not form in the systems, which is confirmed by spontaneous flux crystallization. The α-Rb 2 Pb(MoO 4 ) 2 crystals are obtained and their crystal structure is solved (а = 20.9724(15) Å, b = 12.1261(8) Å, с = 16.1171(10) Å, β = 115.728(13)°, С2/m space group, R = 0.0695, Z = 16), which is a monoclinic superstructure of the palmierite type and has the largest cell volume and the most complex structure among lead-containing palmierites. One of the MoO 6 tetrahedra is orientationally disordered over two sites; lead atoms are shifted from the centers of their coordination polyhedra to one of their faces and have cn = 6-8; for rubidium cations cn = 10-12.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.