|Name, Symbol, Number||Thulium, Tm, 69|
|Group, Period, Block||NA, 6 , f|
|Density, Hardness||9321 kg/m3, no data|
|Atomic weight||168.93421 amu|
|Atomic radius (calc.)||175 (222) pm|
|Covalent radius||ND pm|
|van der Waals radius||ND pm|
|e- 's per energy level||2,8,18,31,8,2|
|Oxidation states (Oxide)||3 (basic)|
|State of matter||solid (__)|
|Melting point||1818 K (2813 °F)|
|Boiling point||2220 K (3537 °F)|
|Molar volume||19.1 ×1010-3 m3/mol|
|Heat of vaporization||191 kJ/mol|
|Heat of fusion||16.84 kJ/mol|
|Vapor pressure||ND Pa at __ K|
|Velocity of sound||ND m/s at 293.15 K|
|Electronegativity||1.25 (Pauling scale)|
|Specific heat capacity||160 J/(kg*K)|
|Electrical conductivity||1.5 106/m ohm|
|Thermal conductivity||16.8 W/(m*K)|
|1st ionization potential||596.7 kJ/mol|
|2nd ionization potential||1160 kJ/mol|
|3rd ionization potential||2285 kJ/mol|
|4th ionization potential||4120 kJ/mol|
|Most stable isotopes|
|SI units & STP are used except where noted.|
|Table of contents|
7 External links
The element is never found in found in nature in pure form but it is found in small quantities in minerals with other rare earths. It is principally extracted from monazite (~0.007% thulium) ores found in river sands through ion-exchange. Newer ion-exchange and solvent extraction techniques have led to easier separation of the rare earths, which has yielded much lower costs for thulium production. The metal can be isolated through reduction of its oxide with lanthanum metal or by calcium reduction in a closed container. None of thulium's compoundss are commercially important.
Naturally occurring thulium is composed of 1 stable isotope, Tm-169 (100% natural abundance). 31 radioisotopes have been characterized, with the most stable being Tm-171 with a half-life of 1.92 years, Tm-170 with a half-life of 128.6 days, Tm-168 with a half-life of 93.1 days, and Tm-167 with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lifes that are less than 64 hours, and the majority of these have half lifes that are less than 2 minutes. This element also has 14 meta states, with the most stable being Tm-164m (t½ 5.1 minutes), Tm-160m (t½ 74.5 seconds) and Tm-155m (t½ 45 seconds).
The isotopes of thulium range in atomic weight from 145.966 amu (Tm-146) to 176.949 amu (Tm-177). The primary decay mode before the most abundant stable isotope, Tm-169, is electron capture, and the primary mode after is beta emission. The primary decay products before Tm-169 are element 68 (erbium) isotopes, and the primary products after are element 70 (ytterbium) isotopes.
See also Ytterby.