Synthesis and crystal structure of new complex oxides K10M2+Mo7O27 (M2+ = Mg, Mn, Co)

The Adaptable Lyonsite Structure

“…However, cation vacancies can only be tolerated to a certain extent before any crystal framework will collapse, and the best way for lyonsite-type molybdates to have an average charge of + 3/2 on the A site is to incorporate a monovalent cation. [ 18,31,32] After the early 1990s, when Mg 2.5 VMoO 8 was shown to be effective for the oxidative dehydrogenation of alkane hydrocarbons, [33] searches for other potentially catalytically active phases focused on the lyonsite structure type and the phases M 2.5 VMoO 8 (M = Mn, Zn, Co) were soon discovered. [34][35][36] In addition to mixed vanadomolybdates, lyonsite-type vanadates were also targeted, and the vanadates Co 4 Fe 3.33 -A C H T U N G T R E N N U N G (VO 4 ) 6 , [37] [39] and Co 5 Cr 2.667 A C H T U N G T R E N N U N G (VO 4 ) 6 [40] were all recognized to be isostructural with NaCo 2.31 A C H T U N G T R E N N U N G (MoO 4 ) 3 and a-Cu 3 Fe 4 A C H T U N G T R E N N U N G (VO 4 ) 6 .…”

Orthomolybdates in the Cs–FeII,III–Mo–O System: Cs4Fe(MoO4)3, Cs2Fe2(MoO4)3 and CsFe5(MoO4)7

“…This model with a disorder of some Mo and O ions is in good agreement with an earlier report on isostructural Rb 4 Mn(MoO 4 ) 3 . [13] Note that the loose crystal structure of Cs 4 Fe(MoO 4 ) 3 could provide fast degradation in contact with moisture. Actually, Cs 4 Fe(MoO 4 ) 3 samples contained water after storage in air for several hours.…”

Rb9–xAg3+xSc2(WO4)9: a new glaserite-related structure type, rubidium disorder, ionic conductivity

“…However, compared with the large group of double tungstates (see, for example, Klevtsov & Klevtsova, 1977;Evdokimov et al, 1991), there exist only a few triple and more complex tungstates Li 3 Ba 2 R 3 (WO 4 ) 8 (R = La, Eu, Gd, Ho, Y) (Li et al, 2009(Li et al, , 2010(Li et al, , 2012Pan et al, 2012;Xiao et al, 2012b;Zeng et al, 2013;Hu et al, 2016;Guo et al, 2018) and Li 3 BaSrLa 3 (WO 4 ) 8 (Wei et al, 2015;Singh & Vaidyanathan, 2017), being filled derivatives of the BaNd 2 (MoO 4 ) 4 type (Kiseleva et al, 1979) and scheelite-like KBaLn(WO 4 ) 3 (Ln = Eu, Gd) (Xiao et al, 2012a;Wang et al, 2017), which are considered as promising laser hosts and phosphors for white LEDs. Recently we prepared a triple tungstate containing no trivalent metals, Cs 3 LiZn 2 (WO 4 ) 4 (Solodovnikov et al, 2017) which is a filled variant of the cation-deficient Cs 6 Zn 5 (MoO 4 ) 8 structure (Solodovnikov et al, 1987), and revealed a new group of silver-ion conducting triple tungstates Ag 1Àx Mg 1Àx R 1+x (WO 4 ) 3 (R = Sc, Al; 0-0.3 x 0.5) of the NASICON type (Kotova et al, 2016).…”