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Holmium single crystal 67Ho164.930
Holmium was discoverd in 1878 by P.T. Cleve at Uppsala, Sweden, and independently by M. Delafontaine and J.L. Soret at Geneva, Switzerland.
[Greek: Holmia = Sweden]
French: holmium
German: holmium
Italian: olmio
Spanish: holmio
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Description: Holmium is a silvery metal of the so-called rare earth group (more correctly
termed the lanthanides). It is slowly attacked by oxygen and water, and dissolves in acids.
Holmium is used as a flux concentrator for high magnetic fields.
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Metal single crystal properties
| State: |
single crystal |
| Crystal structure: |
hexagonal |
| Production method: |
Floating zone |
| Standard size: |
diameter 7-8mm
thickness 1mm |
| Orientation: |
(0001) |
| Orientation accuracy: |
<2°, <1°, <0.5° or <0.1° |
| Polishing: |
as cut, one or two sides polished |
| Roughness of surface: |
<0.03µm |
| Purity: |
99.99% |
Further Materials properties
| Crystal structure: |
(cell dimensions/pm), space group
a-Ho h.c.p. (a=357.73, c=561.58), P63/mmc
b-Ho b.c.c. (a=396), Im3m
T(a -> a)= just below melting point
High pressure form: (a=334, c=2410), R3m |
| X-ray diffractions mass absorption coefficients: |
CuKa 128 (µ/r) / cm2g-1
MoKa 73.9 (µ/r) / cm2g-1 |
| Neutron scattering length: |
0.808 b/10-12 cm |
| Thermal neutron capture cross-section: |
65 sa / barns |
| Density: |
8.8 g/cm3 |
| Melting point: |
1473.85 °C / 1747 °K |
| Boiling point: |
2694.85 °C / 2968 °K |
| Molar volume: |
18.75 cm3 |
| Thermal conductivity: |
16.2 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
9.5 x 10-6 K-1 |
| Electrical resistivity: |
87.0x10-8 [298 K] Wm |
| Mass magnetic susceptibility: |
+5.49 x 10-6(s) kg-1m3 |
| Young's modulus: |
64.8 GPa |
| Rigidity modulus: |
26.3 GPa |
| Bulk modulus: |
40.2 GPa |
| Poisson's ratio: |
0.231 GPa |
| Radii: |
Ho3+ 89; atomic 177; covalent 158 |
| Electronegativity: |
1.23 (Pauling); 1.10 (Allred); £3.3 eV (absolute) |
| Effective nuclear charge: |
2.85 (Slater); 8.44 (Clementi); 11.60 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
39 |
| Issotope mass range: |
148 -> 170 |
Biological data
| Biological role: |
none, but acts to stimulate metabolism |
| Toxicity |
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| Toxic intake: |
n.a. |
| Lethal intake: |
LD50 (chloride, oral, mouse)=7200 mg kg-1 |
| Hazards: |
Holmium is mildly toxic by ingestion |
| Level in humans |
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| Organs: |
n.a., but low |
| Daily dietary intake: |
n.a. |
Total mass of element in average
[70 kg] person: |
n.a. |
Geological data
| Minerals: |
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| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Bastnäsite |
(Ce, La etc.) Co3F |
4.9 |
4 - 4.5 |
hex., vit./greasy yellow |
| Monazite |
(Ce, La, Nd, Th etc.) PO4 |
5.20 |
5 - 5.5 |
mon., waxy/vit., yellow-brown |
| Chief ore: |
monazite, bastnäsite |
| World production: |
c. 10 tonnes/year |
| Main mining areas: |
USA, Brazil, India, Sri Lanka, Australia, China |
| Reserves: |
4 x 105 tonnes |
| Specimen: |
available as ingots or granules. Safe.
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| Abundances |
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| Sun: |
n.a. (relative to H = 1 x 1012) |
| Earth's crust: |
1.4 p.p.m. |
| Seawater: |
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| Atlantic surface: |
2.4 x 10-7 p.p.m. |
| Atlantic deep: |
2.9 x 10-7 p.p.m. |
| Pacific surface: |
1.6 x 10-7 p.p.m. |
| Pacific deep: |
5.8 x 10-7 p.p.m. |
| Residence time:: |
n.a. |
| Classification: |
recycled |
| Oxidation state: |
III |
Other sizes and specifications on request
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