两种不同晶形的邻羟基苯甲酸钬配合物的合成与晶体结构

合成了两种不同晶形的配合物，其组成分别为［Ｈｏ_２（ｏ－ＨＯＣ_６Ｈ_１ＣＯ_２）_６（Ｈ_２Ｏ）_４］·４Ｈ_２Ｏ及［Ｈｏ（ｏ－ＨＯＣ_６Ｈ４ＣＯ_２）_３·（Ｈ_２Ｏ）_２·２Ｈ_２Ｏ］_ｎ，用Ｘ射线衍射法测定了它们的结构：一种以二聚体形式存在，属三斜晶系（Ⅰ），其中钬离子的配位数为９；另一种呈无限链状聚合结构，属单斜晶系（Ⅱ），钬离子的配位数为８．同时还研究了它们的热分解过程．     

On an Unexpected 2D‐linked Rare Earth 1,2,4‐Triazolate Network: Synthesis,Crystal Structure,Spectroscopic and Thermal Properties of $_{\infty}^{2}\rm [Ho(Tz)_{3}(TzH)_{2}]TzH$

The network compound , (Tz^? = 1,2,4‐triazolate anion, C₂H₂N₃^?, TzH = 1,2,4‐1H‐triazole, C₂H₃N₃), was obtained as pink single crystals by the reaction of the holmium metal with a melt of the amine 1,2,4‐1H‐triazole. No additional solvent was used. The compound is an unexpected example of a 2D‐linked network structure as other lanthanides give 3D‐frameworks and MOFs with 1,2,4‐1H‐triazole instead. This illustrates that the series of lanthanides yields very different results in attempts to create MOF structures. In the triazolate ligands Tz^? function both as μ‐η¹:η² linkers as well as η¹ end on ligands. The latter coordination mode is also found for additional triazole molecules. C.N. is nine for holmium(III). The layers exhibit a system of intra and inter layer hydrogen bonding and to triazole molecules from the melt reaction intercalated in‐between the layers. The product was investigated by X‐ray single crystal analysis, Mid IR, Far IR and Raman spectroscopy, and with DTA/TG regarding its thermal behaviour.     

The magnetic structure of the compound Ho5Sb3

We have investigated the magnetic behavior of Ho₅Sb₃ compound (Mn₅Si₃-type, hexagonal; a=0.8865(1) nm, c=0.6232(1) nm, as derived from X-ray Guinier powder pattern) by using the techniques of magnetization, electrical resistivity, heat capacity and neutron diffraction. We find that Ho₅Sb₃ exhibits a ferrimagnetic type (Ferrimagnet I) ordering below 60 K with propagation vectors K₀=[0, 0, 1] and K₁=[±K_x, 0, 0]. Below 40 K, the thermal variation of magnetic reflections and the appearance of an additional magnetic component with propagation vector K₂=[0, 1/2, 0] show the onset of an antiferromagnetic type of ordering in the magnetic structure; which evolves into yet another ferrimagnetic structure (Ferrimagnet II) as the temperature is lowered down to 2 K. The magnetic moments of the Ho atoms at the (4d) and (6g) sites with magnitudes of nearly 7.4 and 6.3 μ_B at 2 K, respectively, are inclined approximately at 70° to the c-axis.     

Ho2Te4O11 und Ho2Te5O13: Zwei tellurdioxidreiche Oxotellurate(IV) des dreiwertigen Holmiums

Ho₂Te₄O₁₁ and Ho₂Te₅O₁₃: Two Telluriumdioxide‐rich Oxotellurates(IV) of Trivalent Holmium Ho₂Te₄O₁₁ (monoclinic, C2/c; a = 1240.73(8), b = 511.21(3), c = 1605.84(9) pm, β = 106.142(7)°; Z = 4) and Ho₂Te₅O₁₃ (triclinic, P1; a = 695.67(5), b = 862.64(6), c = 1057.52(7) pm, α = 89.057(6), β = 86.825(6), γ = 75.056(6)°; Z = 2) are obtained by the reaction of holmium sesquioxide with tellurium dioxide in appropriate molar ratios (Ho₂O₃ : TeO₂ = 1 : 4 and 1 : 5, respectively) in evacuated silica tubes within eight days at 800 °C. The application of cesium chloride (CsCl) as flux in about five times molar excess secures fast and complete reactions to the single‐crystalline products aimed at. In the crystal structure of Ho₂Te₄O₁₁ [HoO₈] polyhedra are connected via oxygen edges thereby building up a network {[Ho₂O₁₀]^14–} (001). On the other hand, the crystal structure of Ho₂Te₅O₁₃ exhibits oxygen‐linked [(Ho1)O₈] and [(Ho2)O₇] polyhedra, which form ribbons {[(Ho1)₂(Ho2)₂O₂₀]^28–} running along [100]. Common to both structures, however, is the stereochemical activity of the non‐bonding electron pairs (“lone pairs”) of all the of the Te⁴⁺ cations (Te1 and Te2 in Ho₂Te₄O₁₁, Te1–Te5 in Ho₂Te₅O₁₃) causing ψ¹‐polyhedral figures of coordination with 3 + 1, 4 and 3 + 2 oxygen atoms, respectively, around the central atoms.     

SrF_2晶体中Ho~(3 )-Ho~(3 )离子对的上转换发光研究

究了在连续可调谐红色染料激光激发下,掺杂Ｈｏ３＋离子的ＳｒＦ２单晶中Ｈｏ３＋Ｈｏ３＋对的上转换发光特性。Ｈｏ３＋Ｈｏ３＋离子对的上转换发光主要分布于：强５Ｆ３→５Ｉ８跃迁４８０ｎｍ蓝色发射,较强５Ｓ２,５Ｆ４→５Ｉ８跃迁的５４０ｎｍ绿色发射。给出了ＳｒＦ２晶体中Ｈｏ３＋离子发射光谱中不同能级跃迁的谱峰及所对应的跃迁。通过对样品的激发,发射光谱和发光的上升、衰减等过程的分析,研究了发光中心的结构,分析了Ｈｏ３＋上转换发光的机制,建立了Ｈｏ３＋Ｈｏ３＋离子对的能级图     

HEH[EHP]萃取色层分离-原子发射光谱测定超高纯氧化钬、氧化铒中痕量稀土杂质

本文研究了２－乙基己基膦酸单２－乙基己酯萃取色层分离－原子发射光谱测定超高纯Ｈｏ２Ｏ３、Ｅｒ２Ｏ３中良量稀土杂质,可用于９９．９９９９％Ｈｏ２Ｏ３、Ｅｒ２Ｏ３的纯度分析。     

Synthese und Kristallstruktur des Holmium(III)‐chlorid‐oxotellurats(IV) HoClTeO3

Synthesis and Crystal Structure of the Holmium(III) Chloride Oxotellurate(IV) HoClTeO₃ Orange coloured, rod—shaped single crystals of the holmium( III) chloride oxotellurate(IV) HoClTeO₃ (orthorhombic, Pnma; a = 730.25(5), b = 696.54(5), c = 905.18(7) pm; Z = 4) are obtained during attempts to synthesize holmium(III) oxochlorotellurates(IV) by reaction of holmium oxychloride (HoOCl) and tellurium dioxide (TeO₂; 1:1—2molar ratio, 800 °C, 40 d) in evacuated silica tubes. The crystal structure contains sevenfold coordinated Ho ³⁺ cations surrounded by five oxide and two chloride anions forming a pentagonal bipyramid. Interconnection of the [Ho(O1)(O2)₄Cl₂] polyhedra occurs via two edges made of four equatorial oxygen atoms (O2) under formation of {[Ho(O1)(O2)_4/2Cl_2/1]^5‐} chains running parallel [010]. These arrange as hexagonal closest packing of rods and are linked to each other by Cl^‐ anions to a three—dimensional {[Ho(O1)_1/1(O2)_4/2Cl_2/2]^4‐} network. All Te⁴⁺ cations are embedded therein and exhibit ψ¹—tetrahedral coordination figures as discrete anionic [Te(O1)(O2)₂]^2‐ pyramids due to the stereochemical activity of the non—binding electron pairs („lone pairs”︁). They stabilize the {[HoO₃Cl]^4‐} network via covalent bonds to one axial (O1) and two equatorial oxygen atoms (O2) of each [HoO₅Cl₂] polyhedron.     

Ho2O[SiO4] und Ho2S[SiO4]: Zwei Chalkogenid‐Derivate von Holmium(III)‐ortho‐ Oxosilicat

Ho₂O[SiO₄] and Ho₂S[SiO₄]: Two Chalcogenide Derivatives of Holmium(III) ortho‐Oxosilicate Ho₂O[SiO₄] crystallizes monoclinically with the space group P2₁/c (a = 904.15(9), b = 688.93(7), c = 667.62(7) pm, β = 106.384(8)°, Z = 4) in the A‐type structure of rare‐earth(III) oxide oxosilicates. Yellow platelet‐shaped single crystals were obtained as by‐product during an experiment to synthesize Ho₃Cl[SiO₄]₂ by reacting Ho₂O₃ and SiO₂ in the ratio 4 : 6 with an excess of HoCl₃ as flux at 1000 °C for seven days in evacuated silica ampoules. Both crystallographically different Ho³⁺ cations show coordination numbers of 8+1 and 7 with coordination figures of 2+1‐fold capped trigonal prisms and octahedra, in which one of the vertices changes to an edge by two instead of one coordinating atoms, respectively. The O^2— anion not linked to silicon is surrounded tetrahedrally by four Ho³⁺ cations which built a layer parallel (100) by vertex‐ and edge‐sharing of the [OHo₄]¹⁰⁺ units according to {[(O5)(Ho1)_1/1(Ho2)_3/3]⁴⁺}. Within rhombic meshes of these layers the isolated oxosilicate tetrahedra [SiO₄]^4— come to lie. Ho₂S[SiO₄] crystallizes orthorhombically in the space group Pbcm (a = 605.87(5), b = 690.41(6), c = 1064.95(9) pm, Z = 4). It also emerged as a single‐crystalline by‐product obtained during the synthesis of Ho₂OS₂ by reaction of a mixture of Ho₂O₃, Ho and S with the wall of the evacuated silica tube used as container with an excess of CsCl as flux at 800 °C. The structure of the yellow platelet‐shaped, air and water resistant crystals also distinguishes two Ho³⁺ cations with bicapped trigonal prisms and trigondodecahedra as coordination polyhedra for CN = 8. The S^2— anions are almost square planar surrounded by four Ho³⁺ cations, but situated completely outside this plane. The [SHo₄]¹⁰⁺ squares form strongly corrugated layers perpendicular to [100] by corner‐sharing according to {[(S)(Ho1)_2/2(Ho2)_2/2]⁴⁺}. Contrary to the oxide oxosilicates the isolated oxosilicate tetrahedra [SiO₄]^4— do not lie within the rhombic meshes of these layers, but above and below the (Ho2)³⁺ cations while viewing along [100].     

Mobility of magnetic helicoid in holmium nano-layer

Spin valves with holmium layers and three-layer structures metal/Ho/metal were prepared by magnetron sputtering. A holmium layer in the spin valves is polycrystalline with weak axial <002> texture. The structural coherence length along the hexagonal c-axis is approximately 2/5 of the total thickness of the holmium layer. Field dependences of the spin valves magnetoresistance were measured at different temperatures. Correlation was revealed between magnetic state in holmium layer and the shape of magnetoresistive curve. Deviation of magnetic moments of the reference layer and the adjacent part of holmium from the applied magnetic field was investigated. The field induced mobility of the magnetic helicoid in holmium layers was revealed.