Английская Википедия:Europium compounds

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Файл:Luminescence of europium compounds.webm
Europium compounds fluoresce under UV light at 395 nm and 365 nm.[1]

Europium compounds are compounds formed by the lanthanide metal europium (Eu). In these compounds, europium generally exhibits the +3 oxidation state, such as EuCl3, Eu(NO3)3 and Eu(CH3COO)3. Compounds with europium in the +2 oxidation state are also known. The +2 ion of europium is the most stable divalent ion of lanthanide metals in aqueous solution.[2] Many europium compounds fluoresce under ultraviolet light due to the excitation of electrons to higher energy levels.[1] Lipophilic europium complexes often feature acetylacetonate-like ligands, e.g., Eufod.

Properties of europium compounds

Formula Color Crystal structure Space group No
EuBr2 white SrBr2 P4/n 85
EuBr3 grey[3] PuBr3 Cmcm 63
EuCl2 white PbCl2 Pnma 62
EuCl3 yellow UCl3 P63/m 176
EuF2 dark yellowish[4] fluorite[5] FmШаблон:Overlinem 225
EuF3 white LaF3[6] Pnma 62
EuI2 yellow monoclinic P21/c 14
EuI3 colorless[7] BiI3 RШаблон:Overline 148
EuH2 dark red[8] PbCl2 Pnma 62
Eu(OH)2 pale yellow[9] orthorhombic P21am[9] 26
Eu(OH)3 pale pink[10] hexagonal P63/m[11] 176
EuO violet[12] fluorite FmШаблон:Overlinem 225
Eu2O3 white monoclinic C2/m 12
EuS black fluorite FmШаблон:Overlinem 225
EuSe black fluorite FmШаблон:Overlinem 225
EuTe black fluorite FmШаблон:Overlinem 225
EuSO4 white orthorhombic Pnma 62

Chalcogenides

Oxides

Europium(II) oxide can be obtained by the reduction of europium(III) oxide with metallic europium at high temperatures. It has a rock-salt structure, is a deep red solid, and is ferromagnetic at 77 K. It has the potential to become a magnetic refrigeration material (ΔSmag=−143 mg/cm3 K，50 kOe).[13][14] Europium(II) sulfide is also ferromagnetic, but europium(II) telluride is antiferromagnetic.[13] The mixed valence oxide Eu3O4 of europium can be obtained by reducing europium(III) oxide with a reducing agent in a hydrogen atmosphere, such as:[5]

2 Eu2O3 + 2 EuOCl + 2 LiH → 2 Eu3O4 + 2 LiCl + H2↑

Europium(III) oxide is the most stable oxide of europium, a light pink solid with a high melting point, which can be obtained by the thermal decomposition of europium(III) nitrate.[13] It reacts with water to give EuOOH.[15] The reaction of soluble europium salts with ammonia or sodium hydroxide can precipitate hydroxide Eu(OH)3, but in the presence of polyhydroxyl compounds (such as glucose), the precipitation is incomplete.[13]

Eu(H2O) and Eu(H2O)2 complexes can be obtained by the reaction of metallic europium in solid argon with water. Eu(H2O) is rearranged to obtain HEuOH, which is further decomposed into EuO and H2; Eu(H2O)2 is decomposed into Eu(OH)2 and H2.[16]

Other chalcogenides

Europium(III) sulfide can be obtained by the decomposition of Eu(Et2NCS2)3 then at 500~600 °C.[17] Europium(III) sulfide can also be obtained by the decomposition of the thiocyanate Eu(NCS)3;[18] Its two crystal forms, α-type and γ-type, belong to orthorhombic and cubic crystal systems, respectively.[19] Europium(II) sulfide is prepared by sulfiding the oxide at temperatures sufficiently high to decompose europium(III) oxide:[20]

Eu2O3 + 3 H2S → 2 EuS + 3 H2O + S

The selenides, europium(III) selenide and europium(II) selenide, and tellurides, europium(II) telluride and europium(III) telluride, are also known. They can generally be prepared by reacting europium with selenium or tellurium in a vacuum ampoule at a high temperature.[21][22][5] Europium(II) selenide can also be obtained by heating europium(II) oxalate with an excess of selenium.

Europium oxysulfide is obtained by reacting europium(III) oxide in a carbon disulfide/argon/low-pressure oxygen stream. It is a solid of the triclinic crystal system, with the space group PШаблон:Overlinem1, and its optical band gap is 4.4 eV.[23] Europium oxyselenide and europium oxytelluride can be prepared by reacting europium(III) oxide with selenium or tellurium at 600 °C.[24] The oxyselenide is heated in air and oxidized to oxyselenite.[25] A similar reaction occurs with oxytelluride to give Eu2TeO6.[26]

Halides

Файл:Europium(III) chloride hexahydrate.jpg
Europium(III) chloride hexahydrate

Europium metal reacts with all the halogens:

2 Eu + 3 X2 → 2 EuX3 (X = F, Cl, Br, I)

This route gives white europium(III) fluoride (EuF3), yellow europium(III) chloride (EuCl3), gray[3] europium(III) bromide (EuBr3), and colorless europium(III) iodide (EuI3). Europium also forms the corresponding dihalides: yellow-green europium(II) fluoride (EuF2), colorless europium(II) chloride (EuCl2) (although it has a bright blue fluorescence under UV light),[27] colorless europium(II) bromide (EuBr2), and green europium(II) iodide (EuI2).[28]

Europium can form all four trihalides. They are strong electrolytes in water, and all but the fluoride are soluble in water. Anhydrous europium trihalides can be prepared by reacting oxides or the halides' hydrates:[29]

Eu2O3 + 6 NH4Cl → 2 EuCl3 + 3 H2O + 6 NH3↑
EuCl3·6H2O + 6 SOCl2 → EuCl3 + 6 SO2↑ + 12 HCl↑

Among them, europium(III) iodide can only be obtained by reacting europium(III) oxide and hydroiodic acid.[30]

In addition, europium can also form all four dihalides. They can generally be prepared by reducing the corresponding europium trihalide with hydrogen gas or europium:

2 EuX3 + H2 → 2 EuX2 + 2 HX

Europium(II) iodide can also be obtained by direct treating the reagent with ammonium iodide.[31] Of the dihalides, EuF2 and EuI2 are yellow, and EuCl2 and EuBr2 are white, although when irradiated by ultraviolet lite, EuCl2 has a bright blue fluorescence.[27]

Pnictides

Europium(III) nitride is a black solid that can be prepared by the reaction of metallic europium in a stream of ammonia in corundum boats in fused quartz tubes at 700 °C:[32]

2 Eu +2 NH3 → 2 EuN + 3 H2

In this reaction, the europium is oxidized and the hydrogen in the ammonia is reduced. Europium(III) nitride shows Van Vleck paramagnetism[33] and crystallises in the rock salt structure.[34][35] Thin films of rare earth nitrides, including europium(III) nitride, tend to form oxides in the presence of oxygen.[36] Europium(III) phosphide can be produced from a solution of europium metal in liquid ammonia with phosphine at -78 °C. This produces hydrogen and first Eu(PH2)2 is formed, but it then decomposes to EuP and PH3.[37][38] It crystallises cubically like NaCl.[39] Pure europium(III) phosphide also shows Van Vleck paramagnetism.[40] Europium(II) diarsenide, Eu2As2, is unique which it contains the Шаблон:Chem2 ion instead of the As3- ion, unlike other lanthanide arsenides. It crystallizes in the distorted Na2O2 structure, similar to nickel arsenide, and is produced from reacting europium and arsenic at 600 °C.[41][42] Other arsenides, antimonides and bismuthides of europium are also known.[43][44][45]

Organoeuropium compounds

Шаблон:See also Organoeuropium compounds are a class of organic metal compounds containing Eu-C bonds. The cyclopentadienyl complexes of europium were studied in the early stage. They can be prepared by the reaction of sodium cyclopentadienide and anhydrous europium halide in tetrahydrofuran, such as:[46][47]

EuCl3 + 3 C5H5Na → (C5H5)3Eu + 3 NaCl
EuI2 + 2 (C5HiPr4)Na → (C5HiPr4)2Eu + 2 NaI

Europium bis(tetraisopropylocene) is an orange-red solid that can be melted at 165 °C.[47] The complex of cyclononatetraene and europium(II) can be prepared by a similar method, and its toluene solution emits blue-green fluorescence at 516 nm, compared with other organic europium(II) sandwich complexes (about 630 nm) with a clear blue shift.[48]

In addition to the preparation of organo-europium compounds by metathesis reaction, metal europium can also be directly involved in the reaction, such as the reaction of europium and pentamethylcyclopentadiene to generate light orange bis(pentamethylcyclopentadiene) europium;[47] and the reaction between cyclooctatetraene and europium gives the pale green cyclooctatetraene europium.[49]

Other compounds

Файл:Formation of europium hydroxide (365 nm UV light).webm
Europium nitrate reacts with sodium hydroxide to form a precipitate of europium hydroxide. The reaction was irradiated with UV light at 365 nm.

Europium(II) sulfate is the sulfate of divalent europium, which can be obtained by electrolysis of europium sulfate solution with mercury as the cathode, or by reducing europium(III) chloride with zinc amalgam, and then reacting with sulfuric acid.[50] It reacts with sodium carbonate or ammonium oxalate to obtain europium(II) carbonate and europium(II) oxalate, respectively:[50]

EuSO4 + Na2CO3 + xH2O → EuCO3·xH2O + Na2SO4
EuSO4 + (NH4)2C2O4(saturated) + H2O → EuC2O4·H2O + (NH4)2SO4

Europium(III) sulfate can be directly obtained by reacting europium(III) oxide and dilute sulfuric acid, and crystallized, and dehydration of hydrate can obtain the anhydrous form. Europium(III) sulfate is soluble in water, and its octahydrate has a solubility of 2.56 g at 20 °C.[51] Europium(III) sulfite (Eu2(SO3)3·nH2O，n=0, 3, 6[52]) and its basic salt (EuOHSO3·4H2O[53]) are known, and heating the sulfite in a carbon monoxide atmosphere will dehydrate to obtain the anhydrous form, and after Eu2O2SO4, finally obtain the oxysulfide Eu2O2S.[54]

Europium(II) hydroxide can be obtained by reacting metallic europium with sodium hydroxide.[9] Europium(II) hydroxide belongs to the orthorhombic crystal system. It decomposes to form europium(III) hydroxide,[55] a pale pink solid that reacts with acids and produces europium(III) salts. It can be prepared by reacting europium with water, or by reacting europium(III) nitrate with hexamethylenetetramine at 95 °C or with ammonium hydroxide.[56][57]

Europium(III) nitrate can be obtained by reacting europium(III) oxide and nitric acid and crystallizing. The crystal is dried with 45~55% sulfuric acid to obtain hexahydrate.[58] Its anhydrous form can be obtained by the reaction of europium oxide and dinitrogen tetroxide, while heating the hydrate can only obtain the basic salt EuONO3.[59] Europium(III) phosphate can be obtained by reacting europium(III) chloride and diammonium hydrogen phosphate (or europium(III) oxide and 5 mol/L phosphoric acid[60]), and its white monohydrate precipitates from solution. It loses water at 600~800 °C, and changes from a hexagonal phase with water to an anhydrous monoclinic phase.[61] Europium(III) oxide reacts with arsenic pentoxide to obtain europium(III) arsenate, which is a colorless crystal with a xenotime structure.[62]

Файл:Europium(III) acetate.jpg
Europium(III) acetate powder

Europium(III) carbonate is one of the carbonates of europium, which can be obtained by reacting a dilute solution of sodium bicarbonate saturated with carbon dioxide with a soluble europium salt. It is heated and decomposed to generate europium(III) oxide and carbon dioxide. Its basic salts and double salts are known.[63] Europium(III) acetate is a pale pink solid that can crystallize from an aqueous solution as the tetrahydrate, which is dried with sulfuric acid to give the trihydrate.[64] The reaction of europium(III) nitrate and oxalic acid gave europium oxalate decahydrate, which was converted to pentahydrate at 100 °C. Using potassium oxalate as raw material can only get double salt KEu(C2O4)2·2H2O.[64] The coordination polymer [Eu(C2O4)(HCOO)]n can be obtained by reacting europium oxalate and oxalic acid with oxalic acid at 200 °C.[65] Europium(III) oxalate is heated to 320 °C in a carbon dioxide atmosphere to obtain europium oxalate:[66]

Eu2(C2O4)3 → 2 EuC2O4 + 2 CO2↑

Applications

Compounds of Eu3+ can emit red light under excitation. For example, europium(III) oxide can be used in picture tube televisions[67] and europium-doped yttrium oxysulfide (Y2O2S:Eu3+) can be used as phosphors.[68] In addition, europium compounds can also be used in the manufacture of anti-counterfeiting materials.[69]

Based on the properties of europium(II) oxide, thin layers of europium(II) oxide deposited on silicon are being studied for use as spin filters. Spin filter materials only allow electrons of a certain spin to pass, blocking electrons of the opposite spin.[70] The synthesis of europium(II) oxide, as well as its europium(II) sulfide, because of their potential as laser window materials, insulating ferromagnets, ferromagnetic semiconductors, and magnetoresistant, optomagnetic, and luminescent materials.[71][72] Europium(II) sulfide was used in an experiment providing evidence of Majorana fermions relevant to quantum computing and the production of qubits.[73]

Eu(OCC(CH3)3CHCOC3F7)3 (abbreviated Eu(fod)3, where the fod ligand is the anion of the commercially available 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione) serves as a Lewis acid catalyst in organic synthesis including stereoselective Diels-Alder and aldol addition reactions. For example, Eu(fod)3 catalyzes the cyclocondensations of substituted dienes with aromatic and aliphatic aldehydes to yield dihydropyrans, with high selectivity for the endo product.[74]

Gallery

Шаблон:Gallery

See also

References

Шаблон:Reflist

External reading

Шаблон:Refbegin

  • Yi Xianwu, Huang Chunhui, Wang Wei, Liu Yujiu, Wu Jinguang. Inorganic Chemistry Series Vol.7 Scandium and Rare Earth Elements. Beijing: Science Press, 1992. ISBN 9787030305749.
  • The Handbook of Synthesis of Inorganic Compounds Vol.2. Beijing: Chemical Industry Press, 1986. CSBN 15063·3726 (Synthesis of Inorganic Compounds II. Tokyo: Maruzen Co., Ltd., 1977) Edited by the Chemical Society of Japan. Translated by An Jiaju and Chen Zhichuan.

Шаблон:Refend

Шаблон:Europium compounds Шаблон:Chemical compounds by element

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  1. ↑ 1,0 1,1 Шаблон:Cite journal
  2. ↑ 无机化学丛书. pp 187-188. 1.2.3 氧化态及电极电势.
  3. ↑ 3,0 3,1 Шаблон:Cite book
  4. ↑ Шаблон:Cite web
  5. ↑ 5,0 5,1 5,2 Шаблон:Cite book
  6. ↑ Шаблон:Cite journal
  7. ↑ Шаблон:Cite book
  8. ↑ Шаблон:Cite journal
  9. ↑ 9,0 9,1 9,2 H. Baernighausen. Lattice constants and space group of the isotypic compounds Eu(OH)2·H2O, Sr(OH)2·H2O, and Ba(OH)2·H2O. Zeitschrift fuer Anorganische und Allgemeine Chemie, 1966. 342 (5-6): 233-239. ISSN: 0044-2313.
  10. ↑ 《无机化学丛书》. 第七卷 钪 稀土元素. 易宪武 等主编. 科学出版社. P168~171. (2)氢氧化物
  11. ↑ Шаблон:Cite journal
  12. ↑ Шаблон:Citation
  13. ↑ 13,0 13,1 13,2 13,3 无机化学丛书. pp 200-203. 2. 氧族化合物; pp 215. 3. 氧化物及氢氧化物.
  14. ↑ Шаблон:Cite journal
  15. ↑ Batsanov, S. S.; Deribas, A. A.; Kustova, G. N. Reaction of rare earth metal oxides with water. Zhurnal Neorganicheskoi Khimii, 1967. 12 (9): 2283-2286. Шаблон:Issn.
  16. ↑ Шаблон:Cite journal
  17. ↑ Kuzmina, N. P.; Ivanov, R. A.; Paramonov, S. E.; Martynenko, L. I. Volatile lanthanide diethyldithiocarbamates as precursors for lanthanide sulfide film deposition. Proceedings - Electrochemical Society, 1997. 97 (25). 880-885. Шаблон:Issn.
  18. ↑ Grizik, A. A.; Eliseev, A. A.; Borodulenko, G. P.; Tolstova, V. A. Low-temperature form of Ln2S3 (Ln = europium, samarium, or gadolinium). Zhurnal Neorganicheskoi Khimii, 1977. 22 (2): 558-559. Шаблон:Issn.
  19. ↑ Шаблон:Cite journal
  20. ↑ Шаблон:Cite book
  21. ↑ Шаблон:Cite book
  22. ↑ Шаблон:Cite journal
  23. ↑ Шаблон:Cite journal
  24. ↑ Sadovskaya, O. A.; Yarembash, E. I.; Eliseev, A. A. Europium oxychalcogenides. Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy, 1974. 10 (11): 2076-2077. Шаблон:Issn.
  25. ↑ Markku Leskela. Thermal stability and infrared absorption spectrum of europium oxyselenide (Eu2O2Se). Finnish Chemical Letters, 1980 (6): 173-176. Шаблон:Issn.
  26. ↑ Шаблон:Cite journal
  27. ↑ 27,0 27,1 Шаблон:Cite journal
  28. ↑ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. p. 1706, Шаблон:ISBN.
  29. ↑ 无机化学丛书. pp 210-215. 2. 卤素化合物
  30. ↑ Emel'yanov, V. I.; Kuznetsova, L. I.; Abramova, L. V.; Ezhov, A. I. Systems Eu2O3-HI-H2O and EuI3-HI-H2O at 25°C. Zhurnal Neorganicheskoi Khimii, 1997. 42(8): 1394-1396.
  31. ↑ Шаблон:Cite journal
  32. ↑ Шаблон:Cite journal
  33. ↑ Шаблон:Cite journal
  34. ↑ Шаблон:Cite journal
  35. ↑ Шаблон:Cite journal
  36. ↑ Шаблон:Cite journal
  37. ↑ Шаблон:Cite journal
  38. ↑ Шаблон:Cite journal
  39. ↑ Шаблон:Citation
  40. ↑ Шаблон:Citation
  41. ↑ Шаблон:Cite journal
  42. ↑ Шаблон:Cite book
  43. ↑ Шаблон:Cite journal
  44. ↑ Шаблон:Cite journal
  45. ↑ Шаблон:Cite journal
  46. ↑ 无机化学丛书. pp 338. 2.3.7 稀土元素有机化合物.
  47. ↑ 47,0 47,1 47,2 Шаблон:Cite journal
  48. ↑ Шаблон:Cite journal
  49. ↑ Шаблон:Cite journal
  50. ↑ 50,0 50,1 无机化学丛书. pp 203. 3. Ln2+的水溶液体系.
  51. ↑ 无机化合物合成手册. pp 258-259. 819 硫酸盐.
  52. ↑ Koskenlinna, Markus; Niinisto, Lauri. Lanthanoid sulfites. III. Preparation and properties of two isomorphous series of lanthanoid sulfite hydrates. Finnish Chemical Letters, 1975. (3-4): 83-88. Шаблон:Issn.
  53. ↑ Шаблон:Cite journal
  54. ↑ Шаблон:Cite journal
  55. ↑ Шаблон:Cite book
  56. ↑ Шаблон:Cite book
  57. ↑ Шаблон:Cite book
  58. ↑ 高胜利, 刘翊纶, 杨祖培. 稀土硝酸盐的制法、性质及结构 Шаблон:Webarchive. 稀土, 1990 (4): 23-28.
  59. ↑ 无机化合物合成手册. pp 260-261. 820 硝酸盐.
  60. ↑ Шаблон:Cite journal
  61. ↑ Шаблон:Cite journal
  62. ↑ Шаблон:Cite journal
  63. ↑ 无机化合物合成手册. pp 261-263. 822 碳酸盐.
  64. ↑ 64,0 64,1 Sarkar, P. B. Some compounds of europium. Bulletin de la Société Chimique de France, 1927. (41): 185-189. Шаблон:Issn.
  65. ↑ Hadi, Abdul Nada; Li, Wei; Feng, Guo-Qiang; Lu, Pei-Xiang. Synthesis, structure, photoluminescence and thermal expansion of a rare earth formate oxalate framework Шаблон:Webarchive. Chinese Journal of Structural Chemistry, 2018. 37 (2): 262-269. DOI: 10.14102/j.cnki.0254-5861.2011-1683.
  66. ↑ Шаблон:Cite journal
  67. ↑ Шаблон:Cite book
  68. ↑ 无机化学丛书. pp 263. 1. 稀土发光材料.
  69. ↑ 魏俊青, 孙诚, 黄利强. 稀土铕配合物在荧光防伪油墨中的应用 Шаблон:Webarchive. 天津科技大学学报, 2012(4):36-39.
  70. ↑ Шаблон:Cite journal
  71. ↑ Шаблон:Cite journal
  72. ↑ Шаблон:Cite journal
  73. ↑ Шаблон:Cite journal
  74. ↑ Wenzel, T.J.; Ciak, J.M.; "Europium, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedianato)" in Encyclopedia of Reagents for Organic Synthesis, 2004. John Wiley & Sons, Ltd. Шаблон:Doi
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