Hydrothermal Synthesis of Lanthanum Vanadates: Synthesis and Crystal Structures of Zircon-Type LaVO4 and a New Compound LaV3O9

Hydrothermal synthesis and structural study of lanthanide orthovanadates, LnVO4 (Ln=Sm, Gd, Dy and Ho)

“…Different groups have employed soft chemistry routes to synthesis LnVO 4 . Surprisingly, only LaVO 4 and YVO 4 have been crystallised under hydrothermal condition [6,11]. Here we report hydrothermal synthesis of single phasic lanthanide vanadates (Ln = Sm, Gd, Dy, Ho) crystallizing in Zircon structure.…”

“…Interestingly, CeVO 4 occurs in three polymorphs zircon, monazite or scheelite structure depending on the pressure employed for the synthesis [10]. It is observed that zircon-type LnVO 4 can be converted to metastable monazite type under pressure but reverse is not possible [6]. Different groups have employed soft chemistry routes to synthesis LnVO 4 .…”

“…Among the binary system Ln 2 O 3 -V 2 O 5 , tetragonal orthovanadates, LnVO 4 are synthesized at higher temperatures and are structurally characterized by powder X-ray diffraction as well as single crystal X-ray diffraction analysis [1][2][3][4][5][6]. Since these solids are potential catalysts for the oxidative dehydrogenation of propane, several attempts have been made to prepare these at relatively lower temperatures either by solid-state reaction or precursor routes [7][8][9].…”

Monazite and Zircon Type LaVO4:Eu Nanocrystals – Synthesis, Luminescent Properties, and Spectroscopic Identification of the Eu3+ Sites

“…Therefore, LaVO 4 crystallizes solely as the monazite type in an equilibrium state and other orthovanadates including those of Sc and Y crystallize as the zircon type. [14] In addition to the thermodynamically stable monazite structure, LaVO 4 can also crystallize as the zircon structure, [15][16][17] a metastable polymorph, under some mild conditions. Therefore, Eu 3+ -doped LaVO 4 can be formed as either the monazite-or zircon type of structure.…”

Mechanochemical synthesis of rare earth orthovanadates from R2O3 (R=rare earth elements) and V2O5 powders

“…These compounds have been synthesized by solid state reactions between constituent oxides at high temperature [10] and wet processes including hydrothermal methods [11][12][13][14]. The former is simple to operate.…”