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sillery white
General properties
Name, seembol, nummer holmium, Ho, 67
Pronunciation /ˈhlmiəm/ HOHL-mee-əm
Element category lanthanide
Group, period, block n/a, 6, f
Staundart atomic wicht 164.93032
Electron confeeguration [Xe] 4f11 6s2
2, 8, 18, 29, 8, 2
Electron shells of holmium (2, 8, 18, 29, 8, 2)
Discovery Marc Delafontaine (1878)
Physical properties
Phase solid
Density (near r.t.) 8.79 g·cm−3
Liquid density at m.p. 8.34 g·cm−3
Meltin pynt 1734 K, 1461 °C, 2662 °F
Boilin pynt 2993 K, 2720 °C, 4928 °F
Heat o fusion 17.0 kJ·mol−1
Heat o vaporization 265 kJ·mol−1
Molar heat capacity 27.15 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1432 1584 (1775) (2040) (2410) (2964)
Atomic properties
Oxidation states 3, 2, 1

(basic oxide)

Electronegativity 1.23 (Pauling scale)
Ionization energies 1st: 581.0 kJ·mol−1
2nd: 1140 kJ·mol−1
3rd: 2204 kJ·mol−1
Atomic radius 176 pm
Covalent radius 192±7 pm
Crystal structure hexagonal close-packed
Holmium has a hexagonal close packed crystal structure
Magnetic orderin paramagnetic
Electrical resistivity (r.t.) (poly) 814 nΩ·m
Thermal conductivity 16.2 W·m−1·K−1
Thermal expansion (r.t.) (poly) 11.2 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2760 m·s−1
Young's modulus 64.8 GPa
Shear modulus 26.3 GPa
Bulk modulus 40.2 GPa
Poisson ratio 0.231
Vickers hairdness 481 MPa
Brinell hairdness 746 MPa
CAS registry nummer 7440-60-0
Most stable isotopes
Main article: Isotopes o holmium
iso NA hauf-life DM DE (MeV) DP
163Ho syn 4570 yr ε 0.003 163Dy
164Ho syn 29 min ε 0.987 164Dy
165Ho 100% 165Ho is stable wi 98 neutrons
166Ho syn 26.763 h β 1.855 166Er
167Ho syn 3.1 h β 1.007 167Er
· r

Holmium is a chemical element wi the seembol Ho an atomic nummer 67. Pairt o the lanthanide series, holmium is a rare yird element. Holmium wis discovered bi Swadish chemist Per Theodor Cleve. Its oxide wis first isolatit frae rare yird ores in 1878 an the element wis named efter the ceety o Stockholm.

Elemental holmium is a relatively saft an malleable sillery-white metal. It is too reactive tae be foond uncombined in naitur, but when isolatit, is relatively stable in dry air at ruim temperatur. However, it reacts wi watter an rusts readily, an will an aa burn in air when heatit.

Holmium is foond in the minerals monazite an gadolinite, an is uisually commercially extractit frae monazite uisin ion exchynge techniques. Its compoonds in naiture, an in nearly aw o its laboratory chemistry, are trivalently oxidized, containin Ho(III) ions. Trivalent holmium ions hae fluorescent properties seemilar tae mony ither rare yird ions (while yieldin thair awn set o unique emission licht lines), an holmium ions are thus uised in the same way as some ither rare yirds in certain laser an glass colorant applications.

Holmium haes the heichest magnetic strength o ony element an tharefore is uised for the polepieces o the strangest static magnets. Acause holmium strangly absorbs neutrons, it is an aa uised in nuclear control rods.

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