Element Thulium
It 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 |
| CAS: | 7440-30-4 |
| Molecular Weight: | 168.934g/mol |
| EC Number : | 231-140-2 |
| MDL Number: | MFCD00011281 |
| Color: | silvery-white |
| Other Names: | Tulio |
| PubChem CID: | 23961 |
| IUPAC Name: | Thulium |
| Inchl: | InChI=1S/Tm |
| InChI Key: | FRNOGLGSGLTDKL-UHFFFAOYSA-N |
| Canonical SMILES: | [Tm] |
| ICSC Number: | n/a |
Physical & Chemical Properties
| Phase: | Solid |
| 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: |   |
| 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 |
| RTECS: | n/a |
| 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
| Isotope | Mass/Da | Natural abundance (atom %) | Nuclear spin (I) | Magnetic moment (μ/μN) |
|---|---|---|---|---|
| 169Tm | 168.934212 (4) | 100 | 1/2 | -0.2316 |
Radiosotope data
| Isotope | Mass/Da | Half-life | Mode of decay | Nuclear spin | Nuclear magnetic moment |
|---|---|---|---|---|---|
| 165Tm | 164.932433 | 1.253 d | EC to 165Er | 1/2 | 0.139 |
| 166Tm | 165.93355 | 7.70 h | EC to 166Er | 2 | 0.092 |
| 167Tm | 166.932849 | 9.24 d | EC to 167Er | 1/2 | -0.197 |
| 168Tm | 167.934171 | 93.1 d | EC to 168Er; β– to 168Yb | 3 | 0.23 |
| 170Tm | 169.935798 | 128.6 d | EC to 170Er; β– to 170Yb | 1 | 0.2476 |
| 171Tm | 170.936426 | 1.92 y | β– to 171Yb | 1/2 | -0.2303 |
| 172Tm | 171.93840 | 2.65 d | β– to 172Yb | 2 |