Effect of Inclining Strain on the Crystal Lattice along an Extended Series of Lanthanide Hydroxysulfates Ln(OH)SO₄(Ln = Pr−Yb, except Pm)

Abstract

A series of trivalent lanthanide hydroxysulfates, Ln(OH)SO(4), (Ln = Pr through Yb, except radioactive Pm) has been synthesized via hydrothermal methods from Ln(2)(SO(4))(3)·8H(2)O by reaction with aqueous NaOH at 170 °C in Teflon lined Parr steel autoclaves, and were characterized by single crystal X-ray diffraction and FT-IR spectroscopy. Two types of arrangements were found in the solid state. The lighter (Ln = Pr-Nd, Sm-Gd) and heavier lanthanide(III) hydroxysulfates (Tb-Yb) are each isostructural. Both structure types exhibit the monoclinic space group P2(1)/n, but the unit cell content is doubled with two crystallographically distinct LnO(8) polyhedra for the heavier lanthanide compounds. The lighter complexes maintain the coordination number 9, forming a three-dimensional extended lattice. The heavier counterparts exhibit the coordination number 8, and arrange as infinite columns of two crystallographically different LnO(8) polyhedra, while extending along the "c" axis. These columns of LnO(8) polyhedra are surrounded and separated by six columns of sulfate ions, also elongating in the "c" direction. The rigid sulfate entities seem to obstruct the closing in of the lighter LnO(9) polyhedra, and show an inclining degree of torsion into the "ac" layers. The crystal lattice of the lighter 4f complexes can sufficiently withstand the tension buildup, caused by the decreasing Ln(3+) radius, up to Gd(OH)SO(4). The energy profile of this structural arrangement then seems to exceed levels at which this structure type is favorable. The lattice arrangement of the heavier Ln-analogues seems to offer a lower energy profile. This appears to be the preferred arrangement for the heavier lanthanide hydroxysulfates, whose crystal lattice exhibits more flexibility, as the coordination sphere of these analogues is less crowded. The IR absorbance frequencies of the hydroxide ligands correlate as a function of the Ln(3+) ionic radius. This corresponds well with the X-ray single crystal analysis data.

Facile and green synthesis of (La0.95Eu0.05)2O2S red phosphors with sulfate-ion pillared layered hydroxides as a new type of precursor: controlled hydrothermal processing, phase evolution and photoluminescence

“…00-045-0750). The compound crystallizes in the space group P 2 1 / n and possesses a layered structure, in which the main layers, composed of LnO 9 polyhedra, are confined to the ac plane and the individual ac layers are tied together by the sulfate entities along the b -axis [1, 17]. The S4 (pH = 9.0) and S5 (pH = 10.0) samples, which were obtained under higher pH, are both indexible to the sulfate-type LRHs (SO 4 2− -LRHs) of Ln 2 (OH) 4 SO 4 ·2H 2 O reported for the intermediately sized Ln 3+ ions (Ln = Pr–Tb) [16].…”

Development of magnetocaloric coordination polymers for low temperature cooling

“…The Gd cations are nine-coordinate and form a capped square antiprism coordination geometry, with six oxygens from the SO 4 2− ligands, with two of the sulfate oxygens being μ 2 -bridging and three oxygens from the OH − anion, this being μ 3bridging. 61 The Gd 3+ cations are connected to form 1D-chains along the a-axis, and these further extend via hydroxy oxygens along the bc direction to form a three-dimensional framework (see Fig. 4).…”

“…4). 61 The magnetic coupling is negligible in this material with a Weiss constant, θ W , of about −0.2 K. The magnetic entropy change −ΔS m of this material was extracted from magnetisation data using the Maxwell relation, with a −ΔS max m value of 53.5 J kg −1 K −1 (276 mJ cm −3 K −1 ) obtained at 2 K and for a 7 T field change, demonstrating a higher gravimetric −ΔS max m than GGG, but a comparable volumetric −ΔS max m to the benchmark material. 47,62 Another family of coordination polymers, the lanthanide orthoborates LnBO 3 , have proven to be viable magnetocalorics for liquid helium temperature regimes at both high and low applied magnetic fields.…”

Structural Complexity and Magnetic Orderings in a Large Family of 3d–4f Heterobimetallic Sulfates

“…Ligands with versatile coordination modes enable the assembly of 3d–4f intermetallic compounds with a vast assortment of structures, which facilitate the elucidation of magneto-structural correlations. As one of the most common inorganic oxoanion with a T d symmetry, sulfate can coordinate with metal ions in diverse ways, including terminal monodentate, terminal bidentate, bridging bidentate, and bridging tridentate, contributing to the structural intricacy of the resulting networks, polynuclear clusters, and even supramolecular assemblies. , Sulfate has proven to be an excellent chelating ligand in the construction of transition-metal hydroxysulfates. − In addition, the unexpected structural complexity of lanthanide sulfate complexes with topologies ranging from a one-dimensional (1D) chain to two-dimensional (2D) layered structures and three-dimensional (3D) frameworks is achieved by adopting a simple sulfate ligand. − Due to the high Lewis acidity of tetravalent actinide cations, the coordination chemistry is further complicated by their strong tendency to hydrolyze in solutions, resulting in the crystallization of polynuclear M IV oxohydroxo sulfate clusters, which can function as secondary building units for open frameworks. , Despite the abundance of homometallic transition-metal-, lanthanide-, and actinide-bearing sulfate complexes, heterobimetallic materials templated by sulfates are relatively uncommon. Examples of these include YM­(OH) 3 (SO 4 ) (M = Cu, Ni), Ln 2 Cu­(SO 4 ) 2 (OH) 4 (Ln = Sm–Dy), , Ce 13 Cr­(HSO 4 ) 6 (SO 4 ) 21 (H 2 O) 75 , [Ln 4 Cr 2 O 2 (OH) 4 (H 2 O) 9 (SO 4 ) 5 ]·3H 2 O (Ln = Gd–Dy), and a family of lanthanide transition-metal tellurite sulfates RE 2 M­(TeO 3 ) 2 (SO 4 ) 2 reported in our previous works. , …”