Holmium

Holmium - Ho

CAS: 7440-60-0
Description: Silver colored metal
Classification: Rare Earth (Lanthanide)
Date of Discovery: 1878
Discoverer: J.L. Soret
Name Origin: Latin Holmia, "Stockholm"

Atomic Number: 67
Number of Neutrons: 98
Atomic Mass: 164.93032(3) amu
Melting Point: 1474 °C
Boiling Point: 2700 °C
Density (25 °C): 8.795 g/cm³
Atomic volume: 18.7 cm³/mol
Electrical resistivity: 0.0124 10^-6/cm

Thermal conductivity: 0.162 W/cmK
Enthalpy of atomization: 301 kJ/mol (est.)
Enthalpy of vaporization: 241.0 kJ/mol
Enthalpy of fusion: 12.20 kJ/mol
Specific heat capacity: 0.16 J/gK

Energy levels: 2-8-18-29-8-2
Electron configuration: [Xe]4f ¹¹6s²
Crystal Structure: Hexagonal
Atomic radius: 2.47 Å
Covalent radius: 1.58 Å
Oxidation States: +3
Electronegativity, Pauling: 1.24
Electron affinity:
First ionization energy: 6.018 eV
2nd ionization energy: 11.805 eV
3rd ionization energy: 22.843 eV
Polarizability: 23.6 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
¹⁴⁴Ho	143.952	0.7 s	⁺, EC
¹⁴⁶Ho	145.9440	3.3 s	⁺, EC	(10+)
¹⁴⁷Ho	146.9396	5.8 s	⁺, EC	11/2-
^148mHo	9 s	⁺, EC	4-
¹⁴⁸Ho	147.9372	2 s	⁺, EC	1+
^149mHo	21 s	⁺, EC	11/2-
¹⁴⁹Ho	148.93379	> 30 s	⁺, EC	1/2+
^150mHo	25 s	⁺, EC	(9+)
¹⁵⁰Ho	149.9326	1.3 m	⁺, EC
^151mHo	47 s	⁺;
¹⁵¹Ho	150.93169	35.2 s	⁺;
^152mHo	50 s	⁺;	(9+)
¹⁵²Ho	151.93166	2.4 m	⁺;	(3+)
^153mHo	9.3 m	⁺;
¹⁵³Ho	152.93020	2.0 m	⁺;	11/2-
^154mHo	3.3 m	⁺; EC	(8+)
¹⁵⁴Ho	153.93060	12 m	⁺, EC	1-
¹⁵⁵Ho	154.92908	⁺, EC	(5/2+)
^156mHo	5.8 m	IT; ⁺; EC
¹⁵⁶Ho	155.9290	56 m	⁺; EC	(5+)
¹⁵⁷Ho	156.92819	12.6 m	⁺; EC	7/2-
^158m2Ho	28 m	IT; EC	2-
^158m1Ho	21 m	⁺, EC	(9+)
¹⁵⁸Ho	157.92895	11.3 m	⁺; EC
^159mHo	8.3 s	IT	1/2+
¹⁵⁹Ho	158.927708	33.0 m	EC	7/2-
^160m2Ho	3 s	1+
^160mHo	5.0 h	IT; EC	2-
¹⁶⁰Ho	159.92873	25.6 m	⁺, EC	5+
^161mHo	6.8 s	IT
¹⁶¹Ho	160.927852	2.48 h	EC	7/2-
^162mHo	1.12 h	IT; EC	6-
¹⁶²Ho	161.929092	15 m	EC, ⁺	1+
^163mHo	1.09 s	IT	(1/2+)
¹⁶³Ho	162.928730	4570 y	^-	7/2-
^164mHo	38 m	IT	(6-)
¹⁶⁴Ho	163.930231	29 m	EC; ^-	1+
¹⁶⁵Ho	100.	164.930319	Stable	7/2-
^166mHo	1200 y	^-	7-
¹⁶⁶Ho	165.932281	1.117 d	^-	0-
¹⁶⁷Ho	166.933127	3.1 h	^-	(7/2-)
^168mHo	2.2 m	IT
¹⁶⁸Ho	167.93550	3.0 m	^-	3+
¹⁶⁹Ho	168.93687	4.7 m	^-	(7/2-)
^170mHo	43 s	^-	1+
¹⁷⁰Ho	169.93962	2.8 m	^-	6+
¹⁷²Ho	25 s	^-
The spectral absorption bands of holmium were noticed in 1878 by the Swiss chemists Delafontaine and Soret, who announced the existence of an "Element X". Cleve, of Sweden, later independently discovered the element while working on erbia earth. The element is named after Cleve's native city. Pure holmia, the yellow oxide, was prepared by Homberg in 1911. Holmium occurs in gadolinite, monazite, and in other rare-earth minerals. It is commercially obtained from monazite, occurring in that mineral to the extent of about 0.05%. It has been isolated by the reduction of its anhydrous chloride or fluoride with calcium metal. Pure holmium has a metallic to bright silver luster. It is relatively soft and malleable, and is stable in dry air at room temperature, but rapidly oxidizes in moist air and at elevated temperatures. The metal has unusual magnetic properties. Few uses have yet been found for the element. The element, as with other rare earths, seems to have a low acute toxic rating. Natural holmium is not radioactive. Holmium has 46 other isotopes known, all of which are radioactive. LINKS: Equilasers, Inc. Holmium Laser for Orthopaedics and Urology Holmium reformation restores function after bleb failure New laser technique eases heart surgery Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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