Energetics of copper diphosphates – Cu2P2O7 and Cu3(P2O6OH)2

Differential scanning calorimetry and high temperature oxide melt solution calorimetry are used to study enthalpy of phase transition and enthalpies of formation of Cu₂P₂O₇ and Cu₃(P₂O₆OH)₂. α-Cu₂P₂O₇ is reversibly transformed to β-Cu₂P₂O₇ at 338–363 K with an enthalpy of phase transition of 0.15 ± 0.03 kJ mol⁻¹. Enthalpies of formation from oxides of α-Cu₂P₂O₇ and Cu₃(P₂O₆OH)₂ are −279.0 ± 1.4 kJ mol⁻¹ and −538.8 ± 2.7 kJ mol⁻¹, and their standard enthalpies of formation (enthalpy of formation from elements) are −2096.1 ± 4.3 kJ mol⁻¹ and −4302.7 ± 6.7 kJ mol⁻¹, respectively. The presence of hydrogen in diphosphate groups changes the geometry of Cu(II) and decreases acid–base interaction between oxide components in Cu₃(P₂O₆OH)₂, thus decreasing its thermodynamic stability.     

IR and Raman spectra of two layered aluminium phosphates Co(en)3Al3P4O16 · 3H2O and [NH4]3[Co(NH3)6]3[Al2(PO4)4]2 · 2H2O

The FT IR and FT Raman spectra of Co(en)₃Al₃P₄O₁₆ · 3H₂O (compound I) and [NH₄]₃[Co(NH₃)₆]₃[Al₂(PO₄)₄]₂ · 2H₂O (compound II) are recorded and analysed based on the vibrations of Co(en)₃³⁺, Co(NH₃)₆³⁺, NH₄⁺, Al---O---P, PO₃, PO₂ and H₂O. The observed splitting of bands indicate that the site symmetry and correlation field effects are appreciable in both the compounds. In compound I, the overtone of CH₂ deformation Fermi resonates with its symmetric stretching vibration. The NH₄ ion in compound II is not free to rotate in the crystalline lattice. Hydrogen bonding of different groups is also discussed.     

Spectroscopic properties of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 and ab initio calculations of [C(NH2)3]2 and HC(NH2)3

Raman and FTIR spectra of guanidinium zinc sulphate [C(NH₂)₃]₂Zn(SO₄)₂ are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO₄²⁻ tetrahedra with distinct S–O bonds. The distortion of the sulphate tetrahedra is attributed to Zn–O–S–O–Zn bridging in the structure as well as hydrogen bonding. The CN₃ group is planar which is expressed in the twofold symmetry along the C–N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH₂)₃]₂ and HC(NH₂)₃ are computed using Gaussian 03 with HF/6-31G* as basis set.     

Novel M(II)–Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu, Ni, Co) and HgCl2

A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)₂HgCl₂ (4), [Co(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.61H₂O (5) and [Ni(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.77H₂O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂(M=Cu(II), Co(II), Ni(II)), with HgCl₂. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) ų, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P , with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) ų, Z=1. Compound 6 also crystallized in the triclinic space group P , with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) ų, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg₂Cl₂ linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂ (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl₂ depending on the metal cation contained within them.     

Influence of several factors on potential-modulated DNA cleavage by the Cu(en)2 and Cu(EDTA) complexes

Potential-modulated DNA cleavage in the presence of copper–ethylenediamine (en) and –ethylenediamine tetraacetic acid (EDTA) complexes was investigated at a gold electrode in a thin layer cell. DNA can be efficiently cleaved through production of active oxygen species at −0.50 V (vs. Ag/AgCl/KCl(sat)) by reducing Cu(en)₂²⁺ to Cu(en)₂⁺ or Cu(EDTA)²⁻ to Cu(EDTA)³⁻. The extent of DNA cleavage increased as the working potential was shifted more negative and the electrolysis time was increased in air-saturated solution. When a small flow of O₂ was passed through the solution during electrolysis, the extent of DNA cleavage was dramatically enhanced. In the absence of Cu(en)₂²⁺ or Cu(EDTA)²⁻ complex, slight DNA cleavage was observed at a more negative working potential due to the reduction of oxygen at the electrode. This observation suggests that potential-modulated DNA cleavage was caused mainly by electrochemical reduction of the Cu(en)₂²⁺ or Cu(EDTA)²⁻ complex in the presence of oxygen. The cleaved DNA fragments were separated by high performance liquid chromatography (HPLC). The experimental results proved that this method of potential-modulated DNA cleavage by Cu(en)₂²⁺ and Cu(EDTA)²⁻ complexes is simple, mild and highly efficient.     

Determination of sulfur contents of SO3, S2O3 and S based on the electrocatalytic interaction with homogeneous mediator tris(2,2'-bipyridyl)Ru(II)

A sensitive voltammetric method has been developed for the determination of total or single species of sulfur anions containing sulfide, sulfite and thiosulfate. The method is based on the catalytic effect of tris(2,2'-bipyridyl)Ruthenium(II) (Ru(bpy)₂^+ 2) as a homogeneous mediator on the oxidation of those anions at the surface of a glassy carbon electrode. A reversible redox couple of Ru(II)/Ru(III) were observed as a solute in aqueous solution. Cyclic voltammetry study showed that the catalytic current of the system depends on the concentration of the anions. Optimum pH values for voltammetric determination of sulfite, thiosulfate and sulfide has been found to be 5.6, 10.0 and 10.0, respectively. Under the optimized conditions the calibration curves have been obtained linear in the concentration ranges of 0.8–500.0, 0.4–1000.0 and 0.5–5000.0 µmol L^− 1 of SO₃²⁻, S₂O₃²⁻ and S²⁻, respectively. The detection limits have been calculated to be 0.40, 0.17 and 0.33 µmol L^− 1 for SO₃²⁻, S₂O₃²⁻ and S²⁻, respectively. The diffusion coefficients of sulfite and thiosulfate have been estimated using chronoamperometry. The chronoamperometric method also has been used to determine the catalytic rate constant for catalytic reaction of the Ru(bpy)₂^+ 2 with sulfite and thiosulfate. Finally the proposed method has been used for the determination of total sulfur contents in real samples of water and wastewater. Moreover the sulfite content in sugar and sulfur dioxide in air has been determined with satisfactory results.     

Spectroscopic and photoelectrochemical differences between racemic and enantiomeric [Ru(phen)3] ions intercalated into layered niobate K4Nb6O17

Chirality effects have been observed in the intercalation, spectroscopic and photoelectrochemical behavior when enantiomeric and racemic [Ru(phen)₃]²⁺ complexes were intercalated in the interlayer spaces of K₄Nb₆O₁₇. The results were interpreted in terms of a [Nb₆O₁₇]⁴⁻-chelate and chelate–chelate interactions. The faster luminescence decay and higher photocurrent of the enantiomeric [Ru(phen)₃]²⁺–K₄Nb₆O₁₇ compounds than the racemic ones suggest that the emission of adsorbed [Ru(phen)₃]²⁺ ions was not only quenched by adsorbed complexes (or concentration quenching) but also by the semiconductive host lattices.     

Preparation and characterization of spherical V2O3 nanopowder

V₂O₃ nanopowder with spherical particles was prepared by reducing pyrolysis of the precursor, (NH₄)₅[(VO)₆(CO₃)₄(OH)₉]·10H₂O, in H₂ atmosphere. The thermolysis process of the precursor in a H₂ flow was investigated by thermogravimetric analysis and differential thermal analysis. The results indicate that pure V₂O₃ forms at 620°C and crystallizes at 730°C. The effects of various reductive pyrolysis conditions on compositions of V₂O₃ products were studied. Scanning electron micrographs show that the particles of the V₂O₃ powder obtained at 650°C for 1 h are spherical about 30 nm in size with more homogeneous distribution. Experiments show that nanopowder has larger adsorption capacity to gases and is more easily reoxidized by air at room temperature than micropowder. Differential scanning calorimetry experiment indicates that the temperature of phase transition of nano-V₂O₃ powder is −119.5°C on cooling or −99.2°C on heating. The transition heats are −12.55 J g⁻¹ on cooling and 11.42 J g⁻¹ on heating, respectively.     

A novel Mo(V) diphosphate with an intersecting tunnel structure: Sr(MoO)2(P2O7)2

A novel Mo(V) diphosphate Sr(MoO)₂P₂O₇ has been synthesized. It crystallizes in the space group P2₁/n with a=7.925(1) Å, b=7.739(1) Å, c=9.485(1) Å and β=91.05(1)°. Its original framework consists of MoP₂O₁₁ units built up of one P₂O₇ group sharing two apices with one MoO₆ octahedron. The MoP₂O₁₁ units share corners, forming [MoP₂O₁₀]_∞ chains running along [101]. The assemblage of these chains forms the [Mo₂P₄O₁₆]_∞ intersecting tunnel framework. The Sr²⁺ cations are located at the tunnel intersection, showing a distorted cubic coordination. This structure is compared to those of Ba(MoO)₂P₂O₇ and LiMoOP₂O₇, which are also built up of MoP₂O₁₁ units forming [MoP₂O₁₀]_∞ chains, but with different configurations.     

Photoluminescence properties of La(PO3)3:Tb under VUV excitation

La_1−x(PO₃)₃:Tb_x³⁺ (0<x0.6) were prepared using solid-state reaction. The vacuum ultraviolet (VUV) excitation spectrum of La_0.55(PO₃)₃:Tb_0.45³⁺ indicates that the absorption of (PO₃)₃³⁻ groups locates at about 163 and 174 nm and the absorption bands of (PO₃)₃³⁻ groups (174 nm) and La³⁺–O²⁻ (200 nm) and Tb³⁺ (213 nm) overlap each other. These results imply that the (PO₃)₃³⁻ groups can efficiently absorb the excited energy around 172 nm and transfer the energy to Tb³⁺. Under 172 nm excitation, the optimal photoluminescence (PL) intensity is obtained when Tb concentration reaches 0.45 and is about 71% of commercial phosphor Zn_1.96SiO₄:0.04 Mn²⁺ with chromaticity coordinates of (0.343, 0.578) and the decay time of about 4.47 ms.     

Preparation and characterization of lithium ion-conducting glass-ceramics in the Li1 + xCrxGe2 − x(PO4)3 system

Li₂O–Cr₂O₃–GeO₂–P₂O₅ based glasses were synthesized by a conventional melt-quenching method and successfully converted into glass-ceramics through heat treatment. Experimental results of DTA, XRD, ac impedance techniques and FESEM indicated that Li_1.4Cr_0.4Ge_1.6(PO₄)₃ glass-ceramics treated at 900 °C for 12 h in the Li_1 + xCr_xGe_2 − x(PO₄)₃ (x = 0–0.8) system exhibited the best glass stability against crystallization and the highest ambient conductivity value of 6.81 × 10⁻⁴ S/cm with an activation energy as low as 26.9 kJ/mol. In addition, the Li_1.4Cr_0.4Ge_1.6(PO₄)₃ glass-ceramics displayed good chemical stability against lithium metal at room temperature. The good thermal and chemical stability, excellent conducting property, easy preparation and low cost make it promising to be used as solid-state electrolytes for all-solid-state lithium batteries.     

Investigation on double perovskite Ba4Ca2Ta2O11

The structure, conductivity and water uptake of the oxygen-deficient perovskite-type compound Ba₄Ca₂Ta₂O₁₁ have been investigated. Ba₄Ca₂Ta₂O₁₁ crystallizes in the cryolite structure (cubic, Fm3m SG) with a = 8.4508(2) Å, under dry air. The compound can be partially hydrated up to a maximum water content of approximately 0.52 mol H₂O per mol Ba₄Ca₂Ta₂O₁₁. In moist air, the structure symmetry becomes monoclinic (C2/m) and the temperature dependence of total conductivity shows a different behavior because of changes in transport mechanism. Three regions can be observed as a function of temperature. For the low temperature range 200–400 °C, the protonic conduction is prevailing with an activation energy E_A = 0.85 eV. In the intermediate temperature range (400–600 °C), O²⁻ anionic and protonic conductions are mixed with an activation energy E_A = 0.45 eV and in the third region, for temperatures above 600 °C, O²⁻conduction is prevailing with an activation energy E_A = 0.85 eV.     

Determination of the bond-angle distribution in vitreous B2O3 by B double rotation (DOR) NMR spectroscopy

The B–O–B bond angle distributions for both ring and non-ring boron sites in vitreous B₂O₃ have been determined by ¹¹B double rotation (DOR) NMR and multiple-quantum (MQ) DOR NMR. The [B₃O₆] boroxol rings are observed to have a mean internal B–O–B angle of 120.0±0.7° with a small standard deviation, σ_R=3.2±0.4°, indicating that the rings are near-perfect planar, hexagonal structures. The rings are linked predominantly by non-ring [BO₃] units, which share oxygens with the boroxol ring, with a mean B_ring–O–B_non-ring angle of 135.1±0.6° and σ_NR=6.7±0.4°. In addition, the fraction of boron atoms, f, which reside in the boroxol rings has been measured for this sample as f=0.73±0.01.     

Syntheses, crystal structures and spectroscopic properties of KEu[AsS4], K3Dy[AsS4]2 and Rb4Nd0.67[AsS4]2

Three rare earth compounds, KEu[AsS₄] (1), K₃Dy[AsS₄]₂ (2), and Rb₄Nd_0.67[AsS₄]₂ (3) have been synthesized employing the molten flux method. The reactions of A₂S₃ (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As₂S₃, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P2₁/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with ²_∞[Eu(AsS₄)]⁻ layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS₈] prisms are linked through distorted [AsS₄]³⁻ tetrahedra. Each Eu²⁺ cation is coordinated by two [AsS₄]³⁻ units by edge-sharing and bonded to further two [AsS₄]³⁻ units by corner-sharing. Compound 2 contains a one-dimensional structure with ¹_∞[Dy(AsS₄)₂]³⁻ chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS₈] are linked by slightly distorted [AsS₄]³⁻ tetrahedra. Each Dy³⁺ ion is surrounded by four [AsS₄]³⁻ moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with ¹_∞[Nd₀.₆₇(AsS₄)₂]⁴⁻ chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As₄]³⁻ units and four terminal [AsS₄]³⁻ groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra.     

Thermoelectric properties of Cu-doped n-type (Bi2Te3)0.9–(Bi2−xCuxSe3)0.1(x=0–0.2) alloys

n-Type (Bi₂Te₃)_0.9–(Bi_2−xCu_xSe₃)_0.1 (x=0–0.2) alloys with Cu substitution for Bi were prepared by spark plasma-sintering technique and their structural and thermoelectric properties were evaluated. Rietveld analysis reveals that approximate 9.0% of Bi atomic sites are occupied by Cu atoms and less than 4.0 wt% second phase Cu_2.86Te₂ precipitated in the Cu-doped parent alloys. Measurements show that an introduction of a small amount of Cu (x0.1) can reduce the lattice thermal conductivity (κ_L), and improve the electrical conductivity and Seebeck coefficient. An optimal dimensionless figure of merit (ZT) value of 0.98 is obtained for x=0.1 at 417 K, which is obviously higher than those of Cu-free Bi₂Se_0.3Te_2.7 (ZT=0.66) and Ag-doped alloys (ZT=0.86) prepared by the same technologies.     

Vibrational spectra of α-Ge(HPO4)2·H2O compound

We have measured Raman and infrared spectra of α-Ge(HPO₄)₂·H₂O compound at room temperature. The analysis of vibrational modes indicated the presence of two non-equivalent HPO₄²⁻ units in agreement with ³¹P nuclear magnetic resonance measurements. A tentative assignment of all the observed modes is proposed based on the previous works reported for other hydrogenphosphate-based compounds.     

Syntheses and X-ray structural studies of the novel complexes [Ni(en)2(3-pyt)2] and [Cu(en)2](3-pyt)2 based on 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione

Two novel mononuclear mixed-ligand complexes [Ni(en)₂(3-pyt)₂] (1) and [Cu(en)₂](3-pyt)₂ (2), derived from potassium [N′-(pyridine-3-carbonyl)-hydrazinecarbodithioate [K⁺(H₂L)⁻] and containing en as a co-ligand, have been synthesized. The [K⁺(H₂L)⁻] undergoes cyclization in the presence of ethylenediamine (en) and is converted to 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione (3-pyt)⁻. [Ni(en)₂(3-pyt)₂] and [Cu(en)₂](3-pyt)₂ have been characterized with the aid of elemental analyses, IR, UV–Vis, magnetic susceptibility and single crystal X-ray studies. The complexes 1 and 2 crystallize in the orthorhombic and monoclinic systems with space groups Pca2(1) and C2/c, respectively. The single crystal X-ray diffraction studies of both complexes indicate that (3-pyt)⁻ adopts a thione form in 1 but is present as a thiolato form in 2.     

Solubility of (UO2)3(PO4)2?4H2O in H+-Na+-OH?-H2PO?4-HPO2?4-PO3?4-H2O and Its Comparison to the Analogous PuO2 +2 System

The objectives of this study were to address uncertainties in the solubility product of (UO₂)₃(PO₄)₂⋅4H₂O(c) and in the phosphate complexes of U(VI), and more importantly to develop needed thermodynamic data for the Pu(VI)-phosphate system in order to ascertain the extent to which U(VI) and Pu(VI) behave in an analogous fashion. Thus studies were conducted on (UO₂)₃(PO₄)₂⋅4H₂O(c) and (PuO₂)₃(PO₄)₂⋅4H₂O(am) solubilities for long-equilibration periods (up to 870 days) in a wide range of pH values (2.5 to 10.5) at fixed phosphate concentrations of 0.001 and 0.01 M, and in a range of phosphate concentrations (0.0001–1.0 M) at fixed pH values of about 3.5. A combination of techniques (XRD, DTA/TG, XAS, and thermodynamic analyses) was used to characterize the reaction products. The U(VI)-phosphate data for the most part agree closely with thermodynamic data presented in Guillaumont et al.,⁽¹⁾ although we cannot verify the existence of several U(VI) hydrolyses and phosphate species and we find the reported value for formation constant of UO₂PO⁻₄ is in error by more than two orders of magnitude. A comprehensive thermodynamic model for (PuO₂)₃(PO₄)₂⋅4H₂O(am) solubility in the H⁺-Na⁺-OH⁻-Cl⁻-H₂PO⁻₄-HPO²⁻₄-PO³⁻₄-H₂O system, previously unavailable, is presented and the data shows that the U(VI)-phosphate system is an excellent analog for the Pu(VI)-phosphate system.     

Ternary [Al2O3–electrolyte–Cu] species: EPR spectroscopy and surface complexation modeling

Cu²⁺ binding on γ-Al₂O₃ is modulated by common electrolyte ions such as Mg²⁺, , and in a complex manner: (a) At high concentrations of electrolyte ions, Cu²⁺ uptake by γ-Al₂O₃ is inhibited. This is partially due to bulk ionic strength effects and, mostly, due to direct competition between Mg²⁺ and Cu²⁺ ions for the SO⁻ surface sites of γ-Al₂O₃. (b) At low concentrations of electrolyte ions, Cu²⁺ uptake by γ-Al₂O₃ can be enhanced. This is due to synergistic coadsorption of Cu²⁺ and electrolyte anions, and _. This results in the formation of ternary surface species (SOH₂SO₄Cu)⁺, (SOH₂PO₄Cu), and (SOH₂HPO₄Cu)⁺ which enhance Cu²⁺ uptake at pH < 6. The effect of phosphate ions may be particularly strong resulting in a 100% Cu uptake by the oxide surface. (c) EPR spectroscopy shows that at pH  pH_PZC, Cu²⁺ coordinates to one SO⁻ group. Phosphate anions form stronger, binary or ternary, surface species than sulfate anions. At pH  pH_PZC Cu²⁺ may coordinate to two SO⁻ groups. At pH  pH_PZC electrolyte ions and are bridging one O-atom from the γ-Al₂O₃ surface and one Cu²⁺ ion forming ternary [γ-Al₂O₃/elecrolyte/Cu²⁺] species.     

Syntheses and Structure Determination of Nine-Coordinate (NH4)3[TbIII(nta)2(H2O)]·4H2O and Eight-Coordinate (NH4)3[ErIII(nta)2] Complexes

Syntheses and structure determination of Tb^III and Er^III complexes with nitrilotriacetic acids (nta) are reported. Their crystal and molecular structures, molecular formulas, and compositions were determined by single-crystal X-ray structure analyses and elementary analyses, respectively. The crystal of the (NH₄)₃[Tb^III(nta)₂(H₂O)]·4H₂O complex belongs to the monoclinic crystal system and C2/c space group. Crystal data are as follows: a = 16.357(8) Å, b = 8.552(4) Å, c = 17.390(9) Å, β = 104.748(7)°, V = 2352.6(19) ų, Z = 4, Mr = 675.32, D_c = 1.932 g·cm⁻³, μ = 3.112 mm⁻¹, and F(000) = 1368. The final R and Rw are 0.0220 and 0.0494 for 2357 (I > 2σ(I)) unique reflections, R and Rw are 0.0266 and 0.0510 for all 5613 reflections, respectively. The Tb^IIIN₂O₇ moiety in the [Tb^III(nta)₂(H₂O)]³⁻ complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure, in which the eight coordinate atoms (two N and six O) are from two nta ligands and the water molecule is coordinated to the central Tb^III ion directly as the ninth coordinate atom. The crystal of the (NH₄)₃[Er^III(nta)₂] complex belongs to the trigonal crystal system and R-3^c space group. Crystal data are as follows: a = 7.9181(16) Å, b = 7.9181(16) Å, c = 54.27(2) Å, γ = 120°, V = 2946.7(14) ų, Z = 6, Mr = 597.61, D _c = 2.021 g·cm⁻³, μ = 4.345 mm⁻¹, and F(000) = 1770. The final R and Rw are 0.0295 and 0.0673 for 677 (I > 2σ(I)) unique reflections, R and Rw are 0.0366 and 0.0700 for all 4827 reflections, respectively. The Er^IIIN₂O₆ part in the [Er^III(nta)₂]³⁻ complex anion is an eight-coordinate structure with a pseudo-dicapped octahedron, in which the eight coordinate atoms (two N and six O) are from two nta ligands.Original Russian Text Copyright © 2004 by J. Wang, X. D. Zhang, Y. Wang, Y. Zhang, Z. R. Liu, J. Tong, and P. L. Kang__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1067–1075, November–December, 2004.