Chemistry:Holmium

From HandWiki

Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.

In nature, holmium occurs together with the other rare-earth metals (like thulium). It is a relatively rare lanthanide, making up 1.4 parts per million of the Earth's crust, an abundance similar to tungsten. Holmium was discovered through isolation by Swedish chemist Per Theodor Cleve. It was also independently discovered by Jacques-Louis Soret and Marc Delafontaine, who together observed it spectroscopically in 1878. Its oxide was first isolated from rare-earth ores by Cleve in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm.[1][2][3]

Like many other lanthanides, holmium is found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion-exchange techniques. Its compounds in nature and in nearly all of its laboratory chemistry are trivalently oxidized, containing Ho(III) ions. Trivalent holmium ions have fluorescent properties similar to many other rare-earth ions (while yielding their own set of unique emission light lines), and thus are used in the same way as some other rare earths in certain laser and glass-colorant applications.

Holmium has the highest magnetic permeability and magnetic saturation of any element and is thus used for the pole pieces of the strongest static magnets. Because holmium strongly absorbs neutrons, it is also used as a burnable poison in nuclear reactors.

Properties

Holmium is the eleventh member of the lanthanide series. In the periodic table, it appears in period 6, between the lanthanides dysprosium to its left and erbium to its right, and above the actinide einsteinium.

Physical properties

With a boiling point of 3,000 K (2,730 °C), holmium is the sixth most volatile lanthanide after ytterbium, europium, samarium, thulium and dysprosium. At standard temperature and pressure, holmium, like many of the second half of the lanthanides, normally assumes a hexagonally close-packed (hcp) structure.[4] Its 67 electrons are arranged in the configuration [Xe] 4f11 6s2, so that it has thirteen valence electrons filling the 4f and 6s subshells.[citation needed]

Holmium, like all of the lanthanides, at paramagnetic in standard temperature and pressure.[5] However, holmium is ferromagnetic at temperatures below 19 K (−254.2 °C; −425.5 °F).[6] It has the highest magnetic moment (10.6 μB) of any naturally occurring element[7] and possesses other unusual magnetic properties. When combined with yttrium, it forms highly magnetic compounds.[8]

Chemical properties

Holmium metal tarnishes slowly in air, forming a yellowish oxide layer that has an appearance similar to that of iron rust. It burns readily to form holmium(III) oxide:[9]

4 Ho + 3 O2 → 2 Ho2O3

It is a relatively soft and malleable element that is fairly corrosion-resistant and chemically stable in dry air at standard temperature and pressure. In moist air and at higher temperatures, however, it quickly oxidizes, forming a yellowish oxide.[10] In pure form, holmium possesses a metallic, bright silvery luster.

Holmium is quite electropositive: on the Pauling electronegativity scale, it has an electronegativity of 1.23.[11] It is generally trivalent. It reacts slowly with cold water and quickly with hot water to form holmium(III) hydroxide:[12]

2 Ho (s) + 6 H2O (l) → 2 Ho(OH)3 (aq) + 3 H2 (g)

Holmium metal reacts with all the stable halogens:[13]

2 Ho (s) + 3 F2 (g) → 2 HoF3 (s) [pink]
2 Ho (s) + 3 Cl2 (g) → 2 HoCl3 (s) [yellow]
2 Ho (s) + 3 Br2 (g) → 2 HoBr3 (s) [yellow]
2 Ho (s) + 3 I2 (g) → 2 HoI3 (s) [yellow]

Holmium dissolves readily in dilute sulfuric acid to form solutions containing the yellow Ho(III) ions, which exist as a [Ho(OH2)9]3+ complexes:[13]

2 Ho (s) + 3 H2SO4 (aq) → 2 Ho3+ (aq) + 3 SO2−4 (aq) + 3 H2 (g)

Oxidation states

As with many lanthanides, holmium is usually found in the +3 oxidation state, forming compounds such as holmium(III) fluoride (HoF3) and holmium(III) chloride (HoCl3). Holmium in solution is in the form of Ho3+ surrounded by nine molecules of water. Holmium dissolves in acids.[7] However, holmium is also found to exist in the +2, +1 and 0 oxidation states.[citation needed]

Isotopes

The isotopes of holmium range from 140Ho to 175Ho. The primary decay mode before the most abundant stable isotope, 165Ho, is positron emission, and the primary mode after is beta minus decay. The primary decay products before 165Ho are terbium and dysprosium isotopes, and the primary products after are erbium isotopes.[14]

Natural holmium consists of one primordial isotope, holmium-165;[7] it is the only isotope of holmium that is thought to be stable, although it is predicted to undergo alpha decay to terbium-161 with a very long half-life.[15] Of the 35 synthetic radioactive isotopes that are known, the most stable one is holmium-163 (163Ho), with a half-life of 4570 years.[16] All other radioisotopes have ground-state half-lives not greater than 1.117 days, with the longest, holmium-166 (166Ho) having a half-life of 26.83 hours,[17] and most have half-lives under 3 hours.

166m1Ho has a half-life of around 1200 years.[18] The high excitation energy, resulting in a particularly rich spectrum of decay gamma rays produced when the metastable state de-excites, makes this isotope useful as a means for calibrating gamma ray spectrometers.[19]

Compounds

Oxides and chalcogenides

Ho2O3, left: natural light, right: under a cold-cathode fluorescent lamp

Holmium(III) oxide is the only oxide of holmium. It changes its color depending on the lighting conditions. In daylight, it has a yellowish color. Under trichromatic light, it appears orange red, almost indistinguishable from the appearance of erbium oxide under the same lighting conditions.[20] The color change is related to the sharp emission lines of trivalent holmium ions acting as red phosphors.[21] Holmium(III) oxide appears pink under a cold-cathode fluorescent lamp.

Other chalcogenides are known for holmium. Holmium(III) sulfide has orange-yellow crystals in the monoclinic crystal system,[14] with the space group P21/m (No. 11).[22] Under high pressure, holmium(III) sulfide can form in the cubic and orthorhombic crystal systems.[23] It can be obtained by the reaction of holmium(III) oxide and hydrogen sulfide at 1,598 K (1,325 °C; 2,417 °F).[24] Holmium(III) selenide is also known. It is antiferromagnetic below 6 K.[25]

Halides

All four trihalides of holmium are known. Holmium(III) fluoride is a yellowish powder that can be produced by reacting holmium(III) oxide and ammonium fluoride, then crystallising it from the ammonium salt formed in solution.[26] Holmium(III) chloride can be prepared in a similar way, with ammonium chloride instead of ammonium fluoride.[27] It has the YCl3 layer structure in the solid state.[28] These compounds, as well as holmium(III) bromide and holmium(III) iodide, can be obtained by the direct reaction of the elements:[13]

2 Ho + 3 X2 → 2 HoX3

In addition, holmium(III) iodide can be obtained by the direct reaction of holmium and mercury(II) iodide, then removing the mercury by distillation.[29]

Organoholmium compounds

Organoholmium compounds are very similar to those of the other lanthanides, as they all share an inability to undergo π backbonding. They are thus mostly restricted to the mostly ionic cyclopentadienides (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.[30]

History

Holmium (Holmia, Latin name for Stockholm) was discovered by the Swiss chemists Jacques-Louis Soret and Marc Delafontaine in 1878 who noticed the aberrant spectrographic emission spectrum of the then-unknown element (they called it "Element X").[31][32]

The Swedish chemist Per Teodor Cleve also independently discovered the element while he was working on erbia earth (erbium oxide). He was the first to isolate the new element.[2][1][33] Using the method developed by the Swedish chemist Carl Gustaf Mosander, Cleve first removed all of the known contaminants from erbia. The result of that effort was two new materials, one brown and one green. He named the brown substance holmia (after the Latin name for Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be the holmium oxide, and thulia was thulium oxide.[34]

In the English physicist Henry Moseley's classic paper on atomic numbers, holmium was assigned the value 66. The holmium preparation he had been given to investigate had been impure, dominated by neighboring (at the time undiscovered) dysprosium. He would have seen x-ray emission lines for both elements, but assumed that the dominant ones belonged to holmium, instead of the dysprosium impurity.[35]

Occurrence and production

A specimen of gadolinite - holmium is the black part of it.

Like all the other rare-earth elements, holmium is not naturally found as a free element. It occurs combined with other elements in gadolinite, monazite and other rare-earth minerals. No holmium-dominant mineral has yet been found. The main mining areas are China, United States, Brazil, India, Sri Lanka, and Australia with reserves of holmium estimated as 400,000 tonnes.[34] The annual production of holmium metal is of about 10 tonnes per year.[36]

Holmium makes up 1.4 parts per million of the Earth's crust by mass. This makes it the 56th most abundant element in the Earth's crust. Holmium makes up 1 part per million of the soils, 400 parts per quadrillion of seawater, and almost none of Earth's atmosphere, which is very rare for a lanthanide.[34] It makes up 500 parts per trillion of the universe by mass.[37]

Holmium is commercially extracted by ion exchange from monazite sand (0.05% holmium), but is still difficult to separate from other rare earths. The element has been isolated through the reduction of its anhydrous chloride or fluoride with metallic calcium.[14] Its estimated abundance in the Earth's crust is 1.3 mg/kg. Holmium obeys the Oddo–Harkins rule: as an odd-numbered element, it is less abundant than both dysprosium and erbium. However, it is the most abundant of the odd-numbered heavy lanthanides. Of the lanthanides, only promethium, thulium, lutetium and terbium are less abundant on Earth. The principal current source are some of the ion-adsorption clays of southern China. Some of these have a rare-earth composition similar to that found in xenotime or gadolinite. Yttrium makes up about two-thirds of the total by mass; holmium is around 1.5%.[38] Holmium is relatively inexpensive for a rare-earth metal with the price about 1000 USD/kg.[39]

Applications

A solution of 4% holmium oxide in 10% perchloric acid, permanently fused into a quartz cuvette as an optical calibration standard

Glass containing holmium oxide and holmium oxide solutions (usually in perchloric acid) have sharp optical absorption peaks in the spectral range 200 to 900 nm. They are therefore used as a calibration standard for optical spectrophotometers.[40][41][42] The radioactive but long-lived 166m1Ho is used in calibration of gamma-ray spectrometers.[43]

Holmium is used to create the strongest artificially generated magnetic fields, when placed within high-strength magnets as a magnetic pole piece (also called a magnetic flux concentrator).[44] Holmium is also used in the manufacture of some permanent magnets.

Holmium-doped yttrium iron garnet (YIG) and yttrium lithium fluoride have applications in solid-state lasers, and Ho-YIG has applications in optical isolators and in microwave equipment (e.g., YIG spheres). Holmium lasers emit at 2.1 micrometres.[45] They are used in medical, dental, and fiber-optical applications.[8] It is also being considered for usage in the enucleation of the prostate.[46]

Since holmium can absorb nuclear fission-bred neutrons, it is used as a burnable poison to regulate nuclear reactors.[34] It is used as a colorant for cubic zirconia, providing pink coloring,[47] and for glass, providing yellow-orange coloring.[48] In March 2017, IBM announced that they had developed a technique to store one bit of data on a single holmium atom set on a bed of magnesium oxide.[49] With sufficient quantum and classical control techniques, holmium may be a good candidate to make quantum computers.[50]

Biological role and precautions

Holmium plays no biological role in humans, but its salts are able to stimulate metabolism.[14] Humans typically consume about a milligram of holmium a year. Plants do not readily take up holmium from the soil. Some vegetables have had their holmium content measured, and it amounted to 100 parts per trillion.[51] Holmium and its soluble salts are slightly toxic if ingested, but insoluble holmium salts are nontoxic. Metallic holmium in dust form presents a fire and explosion hazard.[52][53][54] Large amounts of holmium salts can cause severe damage if inhaled, consumed orally, or injected. The biological effects of holmium over a long period of time are not known. Holmium has a low level of acute toxicity.[55]

See also

References

  1. 1.0 1.1 Marshall, James L. Marshall; Marshall, Virginia R. Marshall (2015). "Rediscovery of the elements: The Rare Earths–The Confusing Years". The Hexagon: 72–77. http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf. Retrieved 30 December 2019. 
  2. 2.0 2.1 "Holmium". 2020. https://www.rsc.org/periodic-table/element/67/holmium. 
  3. Stwertka, Albert (1998). A guide to the elements (2nd ed.). p. 161. 
  4. Strandburg, D. L.; Legvold, S.; Spedding, F. H. (1962-09-15). "Electrical and Magnetic Properties of Holmium Single Crystals". Physical Review 127 (6): 2046–2051. doi:10.1103/PhysRev.127.2046. Bibcode1962PhRv..127.2046S. https://link.aps.org/doi/10.1103/PhysRev.127.2046. 
  5. Cullity, B. D.; Graham, C. D. (2005). Introduction to Magnetic Materials. p. 172. 
  6. Jiles, David (1998). Introduction to magnetism and magnetic materials. p. 228. 
  7. 7.0 7.1 7.2 Emsley, John (2011). Nature's Building Blocks. p. 226. 
  8. 8.0 8.1 C. K. Gupta; Nagaiyar Krishnamurthy (2004). Extractive metallurgy of rare earths. CRC Press. p. 30. ISBN 0-415-33340-7. https://books.google.com/books?id=F0Bte_XhzoAC&pg=PA32. 
  9. Wahyudi, Tatang (2015). "Reviewing the properties of rare earth element-bearing minerals, rare-earth elements and cerium oxide compound" (in en). Indonesian Mining Journal 18 (2): 92–108. doi:10.30556/imj.Vol18.No2.2015.293. ISSN 2527-8797. https://jurnal.tekmira.esdm.go.id/index.php/imj/article/view/293. 
  10. Phillips, W. L. (1964-08-01). "Oxidation of several lanthanide elements" (in en). Journal of the Less Common Metals 7 (2): 139–143. doi:10.1016/0022-5088(64)90056-6. ISSN 0022-5088. https://dx.doi.org/10.1016/0022-5088%2864%2990056-6. 
  11. Winter, Mark J.. "Holmium - 67Ho: electronegativity". University of Sheffield. https://winter.group.shef.ac.uk/webelements/holmium/electronegativity.html#:~:text=Holmium%20%2D%2067Ho%3A%20electronegativity&text=The%20first%20scale%20of%20electronegativity,)%20to%203.98%20(fluorine).. 
  12. An, Tao; Dou, Chunyue; Ju, Jinning; Wei, Wenlong; Ji, Quanzeng (2019-06-01). "Microstructure, morphology, wettability and mechanical properties of Ho2O3 films prepared by glancing angle deposition" (in en). Vacuum 164: 405–410. doi:10.1016/j.vacuum.2019.03.057. ISSN 0042-207X. Bibcode2019Vacuu.164..405A. https://www.sciencedirect.com/science/article/pii/S0042207X19302428. 
  13. 13.0 13.1 13.2 "Chemical reactions of Holmium". Webelements. https://www.webelements.com/holmium/chemistry.html. 
  14. 14.0 14.1 14.2 14.3 C. R. Hammond (2000). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 0-8493-0481-4. 
  15. Belli, P.; Bernabei, R.; Danevich, F. A. et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A 55 (8): 140–1–140–7. doi:10.1140/epja/i2019-12823-2. ISSN 1434-601X. Bibcode2019EPJA...55..140B. 
  16. Naumann, R. A.; Michel, M. C.; Power, J. L. (September 1960). "Preparation of long-lived holmium-163" (in en). Journal of Inorganic and Nuclear Chemistry 15 (1–2): 195–196. doi:10.1016/0022-1902(60)80035-8. 
  17. Suzuki, Yuka S (1998). "Biodistribution and kinetics of holmium-166-chitosan complex (DW-166HC) in rats and mice.". Journal of Nuclar Medicine 39 (12): 2161–2166. PMID 9867162. https://jnm.snmjournals.org/content/jnumed/39/12/2161.full.pdf. 
  18. Klaassen, Nienke J. M.; Arntz, Mark J.; Gil Arranja, Alexandra; Roosen, Joey; Nijsen, J. Frank W. (2019-08-05). "The various therapeutic applications of the medical isotope holmium-166: a narrative review". EJNMMI Radiopharmacy and Chemistry 4 (1): 19. doi:10.1186/s41181-019-0066-3. ISSN 2365-421X. PMID 31659560. 
  19. Oliveira, Bernardes, Estela Maria de (2001-01-01). "Holmium-166m: multi-gamma standard to determine the activity of radionuclides in semiconductor detectors" (in Portuguese). https://inis.iaea.org/search/search.aspx?orig_q=RN:43130653. 
  20. Ganjali, Mohammad Reza; Gupta, Vinod Kumar; Faridbod, Farnoush; Norouzi, Parviz (2016-02-25). Lanthanides Series Determination by Various Analytical Methods. p. 27. 
  21. Su, Yiguo; Li, Guangshe; Chen, Xiaobo; Liu, Junjie; Li, Liping (2008). "Hydrothermal Synthesis of GdVO4:Ho3+ Nanorods with a Novel White-light Emission". Chemistry Letters 37 (7): 762–763. doi:10.1246/cl.2008.762. 
  22. "Ho2S3: crystal structure, physical properties". Non-Tetrahedrally Bonded Binary Compounds II. Landolt-Börnstein - Group III Condensed Matter. 41D. 2000. pp. 1–3. doi:10.1007/10681735_623. ISBN 3-540-64966-2. https://link.springer.com/chapter/10.1007%2F10681735_623. Retrieved 2021-06-22. 
  23. Tonkov, E. Yu (1998). Compounds and Alloys Under High Pressure A Handbook. p. 272. 
  24. Synthesis of Lanthanide and Actinide Compounds. 1991. p. 329. 
  25. Bespyatov, M. A.; Musikhin, A. E.; Naumov, V. N.; Zelenina, L. N.; Chusova, T. P.; Nikolaev, R. E.; Naumov, N. G. (2018-03-01). "Low-temperature thermodynamic properties of holmium selenide (2:3)" (in en). The Journal of Chemical Thermodynamics 118: 21–25. doi:10.1016/j.jct.2017.10.013. ISSN 0021-9614. https://www.sciencedirect.com/science/article/pii/S0021961417303804. 
  26. Riedel, moderne anorganische Chemie. Erwin Riedel, Christoph Janiak, Hans-Jürgen Meyer. De Gruyter. 2012. 
  27. "Holmium chloride | 10138-62-2" (in en). https://www.chemicalbook.com/ChemicalProductProperty_EN_CB0255341.htm. 
  28. Wells, A. F.. Structural inorganic chemistry. p. 421. 
  29. Asprey, L. B.; Keenan, T. K.; Kruse, F. H. (1964). "Preparation and crystal data for lanthanide and actinide triiodides". Inorganic Chemistry 3 (8): 1137–1141. doi:10.1021/ic50018a015. https://digital.library.unt.edu/ark:/67531/metadc867868/. 
  30. Greenwood and Earnshaw, pp. 1248–1249
  31. Jacques-Louis Soret (1878). "Sur les spectres d'absorption ultra-violets des terres de la gadolinite". Comptes rendus de l'Académie des sciences 87: 1062. http://gallica.bnf.fr/ark:/12148/bpt6k3043m/f1124.table. 
  32. Jacques-Louis Soret (1879). "Sur le spectre des terres faisant partie du groupe de l'yttria". Comptes rendus de l'Académie des sciences 89: 521. https://gallica.bnf.fr/ark:/12148/bpt6k3046j/f550.table. 
  33. Weeks, Mary Elvira (1956). The discovery of the elements. Journal of Chemical Education. p. 710. 
  34. 34.0 34.1 34.2 34.3 Emsley, John (2011). Nature's Building Blocks. p. 225. 
  35. Moseley, H.G.J. (1913). "The high-frequency spectra of the elements". Philosophical Magazine. 6th series 26: 1024–1034. https://archive.org/stream/londonedinburg6261913lond#page/1024/mode/2up. 
  36. "Ho - Holmium". MMTA. https://mmta.co.uk/metals/ho/. 
  37. Ltd, Mark Winter, University of Sheffield and WebElements. "WebElements Periodic Table » Periodicity » Abundance in the universe » periodicity". http://www.webelements.com/periodicity/abundance_universe/.. 
  38. Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. pp. 338–339. ISBN 0-07-049439-8. https://books.google.com/books?id=Xqj-TTzkvTEC&pg=PA338. Retrieved 2009-06-06. 
  39. James B. Hedrick. "Rare-Earth Metals". USGS. http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/740798.pdf. 
  40. Allen, David W. (2007). "Holmium oxide glass wavelength standards". Journal of Research of the National Institute of Standards and Technology 112 (6): 303–306. doi:10.6028/jres.112.024. ISSN 1044-677X. PMID 27110474. 
  41. Travis, John C. et al. (2002-06-05). "An International Evaluation of Holmium Oxide Solution Reference Materials for Wavelength Calibration in Molecular Absorption Spectrophotometry". Analytical Chemistry 74 (14): 3408–3415. doi:10.1021/ac0255680. ISSN 0003-2700. PMID 12139047. 
  42. R. P. MacDonald (1964). "Uses for a Holmium Oxide Filter in Spectrophotometry". Clinical Chemistry 10 (12): 1117–20. doi:10.1093/clinchem/10.12.1117. PMID 14240747. http://www.clinchem.org/cgi/reprint/10/12/1117.pdf. 
  43. Ming-Chen Yuan; Jeng-Hung Lee; Wen-Song Hwang (2002). "The absolute counting of 166mHo, 58Co and 88Y". Applied Radiation and Isotopes 56 (1–2): 429–434. doi:10.1016/S0969-8043(01)00226-3. PMID 11839051. 
  44. R. W. Hoard; S. C. Mance; R. L. Leber; E. N. Dalder; M. R. Chaplin; K. Blair et al. (1985). "Field enhancement of a 12.5-T magnet using holmium poles". IEEE Transactions on Magnetics 21 (2): 448–450. doi:10.1109/tmag.1985.1063692. Bibcode1985ITM....21..448H. https://digital.library.unt.edu/ark:/67531/metadc1200738/. 
  45. Wollin, T. A.; Denstedt, J. D. (Feb 1998). "The holmium laser in urology". Journal of Clinical Laser Medicine & Surgery 16 (1): 13–20. doi:10.1089/clm.1998.16.13. PMID 9728125. 
  46. Gilling, Peter J.; Aho, Tevita F.; Frampton, Christopher M.; King, Colleen J.; Fraundorfer, Mark R. (2008-04-01). "Holmium Laser Enucleation of the Prostate: Results at 6 Years" (in en). European Urology 53 (4): 744–749. doi:10.1016/j.eururo.2007.04.052. ISSN 0302-2838. PMID 17475395. https://www.sciencedirect.com/science/article/pii/S0302283807005933. 
  47. Nassau, Kurt (Spring 1981). "Cubic zirconia: An Update.". Gems & Gemology 1: 9–19. doi:10.5741/GEMS.17.1.9. https://www.gia.edu/doc/Cubic-Zirconia.pdf. 
  48. El-Batal, Hatem A.; Azooz, Moenis A.; Ezz-El-Din, Fathy M.; El-Alaily, Nagia A. (2004-12-20). "Interaction of Gamma Rays with Calcium Aluminoborate Glasses Containing Holmium or Erbium" (in en). Journal of the American Ceramic Society 84 (9): 2065–2072. doi:10.1111/j.1151-2916.2001.tb00959.x. https://onlinelibrary.wiley.com/doi/10.1111/j.1151-2916.2001.tb00959.x. 
  49. Coldeway, Devin (March 9, 2017). "Storing data in a single atom proved possible by IBM researchers". https://techcrunch.com/2017/03/08/storing-data-in-a-single-atom-proved-possible-by-ibm-researchers/. 
  50. Forrester, Patrick Robert; Patthey, François; Fernandes, Edgar; Sblendorio, Dante Phillipe; Brune, Harald; Natterer, Fabian Donat (2019-11-19). "Quantum state manipulation of single atom magnets using the hyperfine interaction" (in en). Physical Review B 100 (18): 180405. doi:10.1103/PhysRevB.100.180405. ISSN 2469-9950. Bibcode2019PhRvB.100r0405F. 
  51. Emsley, John (2011). Nature's Building Blocks. p. 224. 
  52. Haley, T. J.; Koste, L.; Komesu, N.; Efros, M.; Upham, H. C. (1966). "Pharmacology and toxicology of dysprosium, holmium, and erbium chlorides". Toxicology and Applied Pharmacology 8 (1): 37–43. doi:10.1016/0041-008x(66)90098-6. PMID 5921895. 
  53. Haley, T. J. (1965). "Pharmacology and toxicology of the rare earth elements". Journal of Pharmaceutical Sciences 54 (5): 663–70. doi:10.1002/jps.2600540502. PMID 5321124. 
  54. Bruce, D. W.; Hietbrink, B. E.; Dubois, K. P. (1963). "The acute mammalian toxicity of rare earth nitrates and oxides". Toxicology and Applied Pharmacology 5 (6): 750–9. doi:10.1016/0041-008X(63)90067-X. PMID 14082480. 
  55. "Holmium: Biological Action". 2011-04-15. http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e06740.html. 

Bibliography

Further reading

  • R. J. Callow, The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium, Pergamon Press, 1967.

External links

  • Holmium at The Periodic Table of Videos (University of Nottingham)