Subsolidus phase relations and structures of solid solutions in the systems K 2 MoO 4 –Na 2 MoO 4 –MMoO 4 (M = Mn, Zn)

Oksana A. Gulyaeva, Zoya A. Solodovnikova, Sergey F. Solodovnikov, Vasiliy N. Yudin, Evgeniya S. Zolotova, Vladislav Yu Komarov

Результат исследования: Научные публикации в периодических изданияхстатья

1 Цитирования (Scopus)

Аннотация

Study of phase formation in the system K 2 MoO 4 –Na 2 MoO 4 at 500 °C showed the existence of the only double molybdate K 2-x Na x MoO 4 (0.4 ≤ x ≤ 1) of the glaserite-related type. Using these data, the subsolidus phase relations in the systems K 2 MoO 4 –Na 2 MoO 4 –MMoO 4 (M = Mn, Zn) were studied at 470–560 °C and the extended solid solutions based on the alluaudite-type Na 4−2x M 1+x (MoO 4 ) 3 were found. In the structure of K 1.71 Na 1.71 Mn 1.29 (MoO 4 ) 3 (sp. gr. C2/c, Z = 4, a = 13.0595(3) Å b = 13.7892(3) Å c = 7.2973(2) Å β = 111.339(1)° R = 0.0134), the potassium ions partially replace Na + in the channels running along c-axis. The structure of K 1.84 Na 2.11 Zn 1.02 (MoO 4 ) 3 (sp. gr. P1̅ Z = 2, a = 7.3258(8) Å b = 9.4128(10) Å c = 9.4302(10) Å α = 93.104(3)° β = 104.573(3)° γ = 104.432(3)° R = 0.0220) is isotypic with alluaudite-related α-K 4 Zn(WO 4 ) 3 and seems to be a result of stabilizing an unknown triclinic modification of K 4 Zn(MoO 4 ) 3 by substitution of sodium for potassium with the strong differentiation of alkali and zinc cations in the structure. In the structure of K 1.5 Na 0.5 Mn 2 (MoO 4 ) 3 (sp. gr. Pcca, Z = 8, a = 10.6160(7) Å b = 12.2714(8) Å c = 18.0275(11) Å R = 0.0155) of the α-K 2 Mn 2 (MoO 4 ) 3 type, one of three initial potassium positions is jointly occupied by (Na, Mn); a similar phenomenon occurs in isostructural Rb 3 Na 3 Sc 2 (MoO 4 ) 6 . The structure contains zigzag-like ribbons of edge-sharing MnO 6 octahedra linked with separate MnO 6 octahedra and МоО 4 tetrahedra into 3D containing channels along the c-axes filled by K + ions. BVS maps show possible one-dimensional sodium-ion conductivity for the structures of K 1.71 Na 1.71 Mn 1.29 (MoO 4 ) 3 and Rb 3 Na 3 Sc 2 (MoO 4 ) 6 .

Язык оригиналаанглийский
Страницы (с-по)148-156
Число страниц9
ЖурналJournal of Solid State Chemistry
Том272
DOI
СостояниеОпубликовано - 1 апр 2019

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