Element Thulium

Thulium ElementIt is the thirteenth and third-last element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.
Thulium is a chemical element with the symbol Tm and atomic number 69.
Pure thulium metal has a bright, silvery luster, which tarnishes on exposure to air.

Names and Identifiers

Chemical Formula:Tm
Molecular Weight:168.934g/mol
EC Number :231-140-2
MDL Number:MFCD00011281
Other Names:Tulio
PubChem CID:23961
IUPAC Name:Thulium
Canonical SMILES:[Tm]
ICSC Number:n/a

Physical & Chemical Properties

Density:9.32 g/cm³
Boiling Point:2223 K ​(1950 °C, ​3542 °F)
Melting Point:1818 K ​(1545 °C, ​2813 °F)
Molecular Formula:Tm
Flash Point:n/a
Exact Mass:168.934204
Symbol:Globally Harmonized System of ClassificationGlobally Harmonized System of Classification
Signal Word:Danger
Hazard Statements:H228-H319-H335
Precautionary Statements:P210-P261-P305 + P351 + P338
Hazard Codes:F,Xi,C
Risk Phrases:15-17-36/37-34-23/24/25
Safety Phrases:S26-S36-S43-S45-S36/37/39-S27
RIDADR:UN 3089 4.1/PG 2
WGK Germany:3
Packaging Group:II
Hazard Class:4.1

The isotopes of thulium range from 145Tm to 179Tm.
The primary decay mode before the most abundant stable isotope, 169Tm, is electron capture, and the primary mode after is beta emission.

Naturally occurring isotopes

IsotopeMass/DaNatural abundance (atom %)Nuclear spin (I)Magnetic moment (μ/μN)
169Tm168.934212 (4)1001/2-0.2316

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
165Tm164.9324331.253 dEC to 165Er1/20.139
166Tm165.933557.70 hEC to 166Er20.092
167Tm166.9328499.24 dEC to 167Er1/2-0.197
168Tm167.93417193.1 dEC to 168Er; β to 168Yb30.23
170Tm169.935798128.6 dEC to 170Er; β to 170Yb10.2476
171Tm170.9364261.92 yβ to 171Yb1/2-0.2303
172Tm171.938402.65 dβ to 172Yb2

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