Synthesis and Aqueous Colloidal Solutions of RE₂(OH)₅NO₃·nH₂O (RE = Nd and La)

Abstract

A new, simple route leading to layered rare-earth hydroxy nitrates was developed. The pH-independent procedure uses ethanol containing alkali-metal hydroxide (KOH, RbOH, or CsOH) as a solvothermal medium. Two new, layered rareearth hydroxy nitrates (LRHs), Nd 2 (OH) 5 NO 3 ·nH 2 O and La 2 (OH) 5 NO 3 ·nH 2 O, were prepared by this nonaqueous solvothermal reaction. Because the RE = Nd and La members have not yet been synthesized in an aqueous system, the successful synthesis of these compounds implies the completion of the RE 2 (OH) 5 NO 3 ·nH 2 O (RE = rare earths) series. The typical properties of a layered structure was demonstrated by ready ion-exchange reactions between NO 3 -and some or-

Well-defined crystallites autoclaved from the nitrate/NH4OH reaction system as the precursor for (Y,Eu)2O3 red phosphor: Crystallization mechanism, phase and morphology control, and luminescent property

“…The hexagonal platelets can be indexed to a layered rare-earth hydroxide (LRH) phase of Ln 2 (OH) 5 NO 3 Á 1.56H 2 O ( Fig. 2(a), Ln¼Y and Eu) [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], where the hydration number was determined via TG analysis up to 260 1C (Fig. S11).…”

“…The most familiar rare-earth precursor compounds are hexagonal Ln(OH) 3 [18][19][20] and monoclinic Ln 4 O(OH) 9 NO 3 [19,20,24] (Ln¼rare earth ions). Recently, some new rare-earth compounds including anion-exchangeable layered hydroxides Ln 2 (OH) 5 (A mÀ ) 1/m Á nH 2 O (Ln¼La, Pr, Nd, Sm-Tm, and Y, A¼intercalated anions) [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], layered hydroxides Yb 2 (OH) 5 NO 3 Á 2H 2 O and Yb 2 (OH) 5 NO 3 Á H 2 O with coordinated NO 3 À accommodated in the gallery of hydroxide layers [43], anion-exchangeable oxy-hydroxide Yb 3 O(OH) 6 Cl Á 2H 2 O with one-dimensional channels containing uncoordinated Cl À [44], and layered hydroxides Ln 2 (OH) 4 SO 4 Á 2H 2 O pillared by sulfate ions [45,46] are reported, and the crystal structures are systematically investigated. The nitrate/NH 4 OH reaction system is one of the simplest for Y 2 O 3 :Eu 3 þ synthesis.…”

Layered Rare Earth Hydroxides: Structural Aspects and Photoluminescence Properties

“…Byeon and coworkers [42] developed a non-aqueous solvothermal route to acquire the target sample. In their strategy, ethanol was selected as a solvent to dissolve the reactants of La(NO 3 ) 3 ·6H 2 O and AOH (A ¼ K, Rb, and Cs).…”

Recent progress in layered rare-earth hydroxide (LRH) and its application in luminescence

“…A series of 251-LRHs, with single-phase products for Sm-Er and Y, have been synthesized by homogeneous precipitation, which involves refluxing an aqueous solution containing the corresponding Ln salt (nitrate or chloride) and hexamethylenetetramine precipitant [6]. Solvothermal reaction, however, is needed to extend the nitrate family of 251-LRHs to the bigger ions of Gd, Eu, Nd, and La [16,17]. The work by McIntyre et al [14] [19].…”