Difference between revisions of "Holmium"
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|alt names= | |alt names= | ||
|allotropes= | |allotropes= | ||
| − | |appearance=Soft, silvery white metal | + | |appearance=Soft, silvery white metal |
<!-- Periodic table --> | <!-- Periodic table --> | ||
| − | |above= | + | |above=- |
|below=Es | |below=Es | ||
| − | |left= | + | |left=[[Dysprosium]] |
| − | |right= | + | |right=[[Erbium]] |
|number=67 | |number=67 | ||
| − | |atomic mass=164 | + | |atomic mass=164.93033(2) |
|atomic mass 2= | |atomic mass 2= | ||
|atomic mass ref= | |atomic mass ref= | ||
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|block ref= | |block ref= | ||
|block comment= | |block comment= | ||
| − | |electron configuration= | + | |electron configuration=[Xe] 4f<sup>11</sup> 6s<sup>2</sup> |
|electron configuration ref= | |electron configuration ref= | ||
|electron configuration comment= | |electron configuration comment= | ||
| − | |electrons per shell= | + | |electrons per shell=2, 8, 18, 29, 8, 2 |
|electrons per shell ref= | |electrons per shell ref= | ||
|electrons per shell comment= | |electrons per shell comment= | ||
<!-- Physical properties --> | <!-- Physical properties --> | ||
|physical properties comment= | |physical properties comment= | ||
| − | |color= | + | |color=Silvery-white |
| − | |phase= | + | |phase=Solid |
|phase ref= | |phase ref= | ||
|phase comment= | |phase comment= | ||
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|density gplstp ref= | |density gplstp ref= | ||
|density gplstp comment= | |density gplstp comment= | ||
| − | |density gpcm3nrt= | + | |density gpcm3nrt=8.79 |
|density gpcm3nrt ref= | |density gpcm3nrt ref= | ||
|density gpcm3nrt comment= | |density gpcm3nrt comment= | ||
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|density gpcm3nrt 3 ref= | |density gpcm3nrt 3 ref= | ||
|density gpcm3nrt 3 comment= | |density gpcm3nrt 3 comment= | ||
| − | |density gpcm3mp= | + | |density gpcm3mp=8.34 |
|density gpcm3mp ref= | |density gpcm3mp ref= | ||
|density gpcm3mp comment= | |density gpcm3mp comment= | ||
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|critical point ref= | |critical point ref= | ||
|critical point comment= | |critical point comment= | ||
| − | |heat fusion= | + | |heat fusion=17 |
|heat fusion ref= | |heat fusion ref= | ||
|heat fusion comment= | |heat fusion comment= | ||
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|heat fusion 2 ref= | |heat fusion 2 ref= | ||
|heat fusion 2 comment= | |heat fusion 2 comment= | ||
| − | |heat vaporization= | + | |heat vaporization=251 |
|heat vaporization ref= | |heat vaporization ref= | ||
|heat vaporization comment= | |heat vaporization comment= | ||
| − | |heat capacity= | + | |heat capacity=27.15 |
|heat capacity ref= | |heat capacity ref= | ||
|heat capacity comment= | |heat capacity comment= | ||
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|heat capacity 2 ref= | |heat capacity 2 ref= | ||
|heat capacity 2 comment= | |heat capacity 2 comment= | ||
| − | |vapor pressure 1= | + | |vapor pressure 1=1432 |
| − | |vapor pressure 10= | + | |vapor pressure 10=1584 |
| − | |vapor pressure 100= | + | |vapor pressure 100=(1775) |
| − | |vapor pressure 1 k= | + | |vapor pressure 1 k=(2040) |
| − | |vapor pressure 10 k= | + | |vapor pressure 10 k=(2410) |
| − | |vapor pressure 100 k= | + | |vapor pressure 100 k=(2964) |
|vapor pressure ref= | |vapor pressure ref= | ||
|vapor pressure comment= | |vapor pressure comment= | ||
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<!-- Atomic properties --> | <!-- Atomic properties --> | ||
|atomic properties comment= | |atomic properties comment= | ||
| − | |oxidation states= | + | |oxidation states='''3''', 2, 1 |
|oxidation states ref= | |oxidation states ref= | ||
| − | |oxidation states comment= | + | |oxidation states comment=(a basic oxide) |
| − | |electronegativity= | + | |electronegativity=1.23 |
|electronegativity ref= | |electronegativity ref= | ||
|electronegativity comment= | |electronegativity comment= | ||
| − | |ionization energy 1= | + | |ionization energy 1=581 |
|ionization energy 1 ref= | |ionization energy 1 ref= | ||
|ionization energy 1 comment= | |ionization energy 1 comment= | ||
| − | |ionization energy 2= | + | |ionization energy 2=1140 |
|ionization energy 2 ref= | |ionization energy 2 ref= | ||
|ionization energy 2 comment= | |ionization energy 2 comment= | ||
| − | |ionization energy 3= | + | |ionization energy 3=2204 |
|ionization energy 3 ref= | |ionization energy 3 ref= | ||
|ionization energy 3 comment= | |ionization energy 3 comment= | ||
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|ionization energy ref= | |ionization energy ref= | ||
|ionization energy comment= | |ionization energy comment= | ||
| − | |atomic radius= | + | |atomic radius=176 |
|atomic radius ref= | |atomic radius ref= | ||
|atomic radius comment= | |atomic radius comment= | ||
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|atomic radius calculated ref= | |atomic radius calculated ref= | ||
|atomic radius calculated comment= | |atomic radius calculated comment= | ||
| − | |covalent radius= | + | |covalent radius=192±7 |
|covalent radius ref= | |covalent radius ref= | ||
|covalent radius comment= | |covalent radius comment= | ||
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|crystal structure prefix= | |crystal structure prefix= | ||
|crystal structure ref= | |crystal structure ref= | ||
| − | |crystal structure comment= | + | |crystal structure comment=Hexagonal close-packed (hcp) |
|crystal structure 2= | |crystal structure 2= | ||
|crystal structure 2 prefix= | |crystal structure 2 prefix= | ||
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|speed of sound ref= | |speed of sound ref= | ||
|speed of sound comment= | |speed of sound comment= | ||
| − | |speed of sound rod at 20= | + | |speed of sound rod at 20=2760 |
|speed of sound rod at 20 ref= | |speed of sound rod at 20 ref= | ||
|speed of sound rod at 20 comment= | |speed of sound rod at 20 comment= | ||
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|speed of sound rod at r.t. ref= | |speed of sound rod at r.t. ref= | ||
|speed of sound rod at r.t. comment= | |speed of sound rod at r.t. comment= | ||
| − | |thermal expansion= | + | |thermal expansion=11.2 |
|thermal expansion ref= | |thermal expansion ref= | ||
| − | |thermal expansion comment= | + | |thermal expansion comment=(poly) |
|thermal expansion at 25= | |thermal expansion at 25= | ||
|thermal expansion at 25 ref= | |thermal expansion at 25 ref= | ||
|thermal expansion at 25 comment= | |thermal expansion at 25 comment= | ||
| − | |thermal conductivity= | + | |thermal conductivity=16.2 |
|thermal conductivity ref= | |thermal conductivity ref= | ||
|thermal conductivity comment= | |thermal conductivity comment= | ||
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|thermal diffusivity ref= | |thermal diffusivity ref= | ||
|thermal diffusivity comment= | |thermal diffusivity comment= | ||
| − | |electrical resistivity= | + | |electrical resistivity=8.14·10<sup>-7</sup> |
|electrical resistivity unit prefix= | |electrical resistivity unit prefix= | ||
|electrical resistivity ref= | |electrical resistivity ref= | ||
| − | |electrical resistivity comment= | + | |electrical resistivity comment=(poly) |
|electrical resistivity at 0= | |electrical resistivity at 0= | ||
|electrical resistivity at 0 ref= | |electrical resistivity at 0 ref= | ||
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|Curie point ref= | |Curie point ref= | ||
|Curie point comment= | |Curie point comment= | ||
| − | |magnetic ordering= | + | |magnetic ordering=Paramagnetic |
|magnetic ordering ref= | |magnetic ordering ref= | ||
|magnetic ordering comment= | |magnetic ordering comment= | ||
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|tensile strength ref= | |tensile strength ref= | ||
|tensile strength comment= | |tensile strength comment= | ||
| − | |Young's modulus= | + | |Young's modulus=64.8 |
|Young's modulus ref= | |Young's modulus ref= | ||
|Young's modulus comment= | |Young's modulus comment= | ||
| − | |Shear modulus= | + | |Shear modulus=26.3 |
|Shear modulus ref= | |Shear modulus ref= | ||
|Shear modulus comment= | |Shear modulus comment= | ||
| − | |Bulk modulus= | + | |Bulk modulus=40.2 |
|Bulk modulus ref= | |Bulk modulus ref= | ||
|Bulk modulus comment= | |Bulk modulus comment= | ||
| − | |Poisson ratio= | + | |Poisson ratio=0.231 |
|Poisson ratio ref= | |Poisson ratio ref= | ||
|Poisson ratio comment= | |Poisson ratio comment= | ||
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|Mohs hardness 2 ref= | |Mohs hardness 2 ref= | ||
|Mohs hardness 2 comment= | |Mohs hardness 2 comment= | ||
| − | |Vickers hardness= | + | |Vickers hardness=410–600 |
|Vickers hardness ref= | |Vickers hardness ref= | ||
|Vickers hardness comment= | |Vickers hardness comment= | ||
| − | |Brinell hardness= | + | |Brinell hardness=500–1250 |
|Brinell hardness ref= | |Brinell hardness ref= | ||
|Brinell hardness comment= | |Brinell hardness comment= | ||
| − | |CAS number= | + | |CAS number=7440-60-0 |
|CAS number ref= | |CAS number ref= | ||
|CAS number comment= | |CAS number comment= | ||
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|prediction date ref= | |prediction date ref= | ||
|prediction date= | |prediction date= | ||
| − | |discovered by= | + | |discovered by=Jacques-Louis Soret |
|discovery date ref= | |discovery date ref= | ||
| − | |discovery date= | + | |discovery date=1878 |
|first isolation by= | |first isolation by= | ||
|first isolation date ref= | |first isolation date ref= | ||
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==Properties== | ==Properties== | ||
===Physical properties=== | ===Physical properties=== | ||
| − | As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a [[neodymium magnet]]. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting. | + | As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a [[Neodymium iron boron magnet|neodymium magnet]]. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting. |
===Chemical properties=== | ===Chemical properties=== | ||
| − | Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a | + | Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a [https://www.flickr.com/photos/37388341@N00/2696039566/in/photostream/ yellow] or [https://www.flickr.com/photos/37388341@N00/2381429226/ green] flame to form holmium oxide. (The green color is likely the true color of burning holmium; the yellow color may be black-body radiation from the products.) Holmium is almost exclusively trivalent, and it is extremely difficult to reduce or oxidize holmium salts. It also reacts with the halogens to form colorful halides, which have the same color-changing properties under different light sources. |
Holmium carbonate may form a soluble complex, but can be broken by addition of [[hydrogen peroxide]]. | Holmium carbonate may form a soluble complex, but can be broken by addition of [[hydrogen peroxide]]. | ||
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==Isolation== | ==Isolation== | ||
| − | Holmium can be obtained by reducing holmium salts, like holmium(III) chloride, with calcium metal. | + | Holmium can be obtained by reducing holmium salts, like holmium(III) chloride, with [[calcium]] metal in a thermite-like reaction. |
| − | ==Projects== | + | ==Projects== |
| + | *Make holmium compounds | ||
*Color changing crystals. | *Color changing crystals. | ||
*Magnet polepieces? | *Magnet polepieces? | ||
| + | *Element collecting | ||
==Safety== | ==Safety== | ||
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===Flammability=== | ===Flammability=== | ||
| − | Small pieces of holmium metal or powder are flammable. Class D [[fire | + | Small pieces of holmium metal or powder are flammable. Class D [[fire extinguisher]]s should be readily available when working with large amounts of holmium near an open flame. Water should never be used to extinguish burning holmium, as it will aggravate the flame. |
===Disposal=== | ===Disposal=== | ||
| − | Due to holmium's rarity, | + | Due to holmium's rarity, it's best to recycle it. |
==References== | ==References== | ||
Latest revision as of 21:44, 27 March 2019
 | |||||
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Holmium, Ho | ||||
| Appearance | Soft, silvery white metal | ||||
| Holmium in the periodic table | |||||
| |||||
| Atomic number | 67 | ||||
| Standard atomic weight (Ar) | 164.93033(2) | ||||
| Group, block | , f-block | ||||
| Period | period 6 | ||||
| Electron configuration | [Xe] 4f11 6s2 | ||||
per shell | 2, 8, 18, 29, 8, 2 | ||||
| Physical properties | |||||
| Silvery-white | |||||
| Phase | Solid | ||||
| Melting point | 1734 K (1461 °C, 2662 °F) | ||||
| Boiling point | 2873 K (2600 °C, 4712 °F) | ||||
| Density near r.t. | 8.79 g/cm3 | ||||
| when liquid, at | 8.34 g/cm3 | ||||
| Heat of fusion | 17 kJ/mol | ||||
| Heat of | 251 kJ/mol | ||||
| Molar heat capacity | 27.15 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 3, 2, 1 (a basic oxide) | ||||
| Electronegativity | Pauling scale: 1.23 | ||||
| energies |
1st: 581 kJ/mol 2nd: 1140 kJ/mol 3rd: 2204 kJ/mol | ||||
| Atomic radius | empirical: 176 pm | ||||
| Covalent radius | 192±7 pm | ||||
| Miscellanea | |||||
| Crystal structure | Hexagonal close-packed (hcp) | ||||
| Speed of sound thin rod | 2760 m/s (at 20 °C) | ||||
| Thermal expansion | 11.2 µm/(m·K) (poly) | ||||
| Thermal conductivity | 16.2 W/(m·K) | ||||
| Electrical resistivity | 8.14·10-7 Ω·m (poly) | ||||
| Magnetic ordering | Paramagnetic | ||||
| Young's modulus | 64.8 GPa | ||||
| Shear modulus | 26.3 GPa | ||||
| Bulk modulus | 40.2 GPa | ||||
| Poisson ratio | 0.231 | ||||
| Vickers hardness | 410–600 MPa | ||||
| Brinell hardness | 500–1250 MPa | ||||
| CAS Registry Number | 7440-60-0 | ||||
| History | |||||
| Discovery | Jacques-Louis Soret (1878) | ||||
Holmium is a lanthanide with the atomic number 67 and the symbol Ho. It is a gray metal that is reactive and slightly magnetic at room temperature. Holmium is difficult to find and somewhat expensive, but has some interesting properties regarding its magnetism and narrow absorption bands.
Contents
Properties
Physical properties
As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a neodymium magnet. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting.
Chemical properties
Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a yellow or green flame to form holmium oxide. (The green color is likely the true color of burning holmium; the yellow color may be black-body radiation from the products.) Holmium is almost exclusively trivalent, and it is extremely difficult to reduce or oxidize holmium salts. It also reacts with the halogens to form colorful halides, which have the same color-changing properties under different light sources.
Holmium carbonate may form a soluble complex, but can be broken by addition of hydrogen peroxide.
Holmium trifluoroacetate and holmium trifluoromethanesulfonate (triflate) are relatively recently discovered catalysts for organic reactions. Even though they are Lewis acids, they do not hydrolyze readily and can be used in numerous solvents. Other lanthanide triflates have been investigated for catalytic activity.
Availability
Holmium is more common than iodine on Earth, but it is very hard to find. For a lanthanides, it is cheaper than some other metals. One source for holmium, as well as other rare earth metals, is Metallium. It is sold in 5 gram and 50 gram sizes, as well as rods, ampoules, and coins. Holmium and its compounds are occasionally sold on eBay as well.
Isolation
Holmium can be obtained by reducing holmium salts, like holmium(III) chloride, with calcium metal in a thermite-like reaction.
Projects
- Make holmium compounds
- Color changing crystals.
- Magnet polepieces?
- Element collecting
Safety
Storage
Bulk holmium metal is stable in air indefinitely. As a powder or fine turnings, it may be extremely flammable, and should be kept away from ignition sources.
Toxicity
Holmium and its compounds have not been thoroughly investigated for toxicity, but no adverse effects have been reported from exposure.
Flammability
Small pieces of holmium metal or powder are flammable. Class D fire extinguishers should be readily available when working with large amounts of holmium near an open flame. Water should never be used to extinguish burning holmium, as it will aggravate the flame.
Disposal
Due to holmium's rarity, it's best to recycle it.
References
- flickr.com/photos/37388341@N00/2696039566/in/photostream/
- flickr.com/photos/37388341@N00/2381429226/
