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thulium

Also known as Tm, element 69, 69Tm

Thulium is a chemical element; it has symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. It is the second-least abundant lanthanide in the Earth's crust, after radioactively unstable promethium. It is an easily workable metal with a bright silvery-gray luster. It is fairly soft and slowly tarnishes in air. Despite its high price and rarity, thulium is used as a dopant in solid-state lasers. It has no significant biological role and is not particularly toxic. Artificial radioactive isotopes of thulium are used as radiation sources in some portable X

OverviewAI-generated

Thulium is a chemical element with the symbol Tm and atomic number 69. Its IUPAC name is thulium, and it is represented by the chemical formula Tm. The element has a mass of 168.934219 and an ionic radius of 1.09. It possesses an electronegativity of 1. The Unicode character for thulium is 銩.

The element was discovered in 1879. In chemical databases, it is identified by the PubChem CID 23961 and the InChIKey FRNOGLGSGLTDKL-UHFFFAOYSA-N. Its molecular weight is listed as 168.93422. Thulium has zero hydrogen bond donors and acceptors, with a topological polar surface area of 0 and a charge of 0. The canonical SMILES representation is [Tm].

Thulium is referenced by 766 other encyclopedia articles. PubMed contains 2600 records associated with the query thulium. The subject is categorized under the Commons category "Thulium" and has a corresponding gallery.

Synthesized by Vinony from 23 facts across 4 sources: Wikidata, PubChem, PubMed, Vinony graph. Generated from structured data (not the Wikipedia text) and checked against those facts — may still contain errors.

Chemical data

Formula: Tm
Molecular weight: 168.93422 g/mol
IUPAC name: thulium
SMILES: [Tm]
InChIKey: FRNOGLGSGLTDKL-UHFFFAOYSA-N
Polar surface area: 0 Å²
H-bond donors: 0
H-bond acceptors: 0
Formal charge: 0

via PubChem

Research

2,600 papers

Pulsed Thulium:YAG Laser for Lithotripsy.ReviewEuropean urology focus · 2025Hernandez-Gaytan CA, Proietti S, Leonardis F et al.DOI: 10.1016/j.euf.2025.06.002
Thulium Fiber Versus Holmium:Yttrium-aluminum-garnet Laser for Endoscopic Enucleation of the Prostate: A Systematic Review and Meta-analysis.European urology focus · 2024Uleri A, Long Depaquit T, Farré A et al.DOI: 10.1016/j.euf.2024.06.005
Thulium fiber laser in urology: physics made simple.ReviewCurrent opinion in urology · 2022Taratkin M, Azilgareeva C, Cacciamani GE et al.DOI: 10.1097/MOU.0000000000000967
[Thulium or holmium laser or both: where will the journey take us?].ReviewAktuelle Urologie · 2024Becker B, Hook S, Gross AJ et al.DOI: 10.1055/a-2286-1379
Thulium Fiber Laser Behavior on Tissue During Upper- and Lower-Tract Endourology.ReviewCurrent urology reports · 2022Gkolezakis V, Rice P, Somani BK et al.DOI: 10.1007/s11934-022-01117-6
Thulium fibre laser lithotripsy, the new standard?BJU international · 2023Grasso M 3rdDOI: 10.1111/bju.15943
Thulium fiber laser utilization in urological surgery: A narrative review.ReviewInvestigative and clinical urology · 2021Khusid JA, Khargi R, Seiden B et al.DOI: 10.4111/icu.20200467
Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser.ReviewWorld journal of urology · 2020Traxer O, Keller EXDOI: 10.1007/s00345-019-02654-5

via PubMed

~12 min read

Encyclopedic overview

15 sections

Contents

Properties
Physical properties
Chemical properties
Isotopes
History
Occurrence
Production
Applications
Lasers
X-ray source
Others
Biological role
See also
References
External links

In 1879, the Swedish chemist Per Teodor Cleve separated two previously unknown components, which he called holmia and thulia, from the rare-earth mineral erbia; these were the oxides of holmium and thulium, respectively. His example of thulium oxide contained impurities of ytterbium oxide. A relatively pure sample of thulium oxide was first obtained in 1911. The metal itself was first obtained in 1936 by Wilhelm Klemm and Heinrich Bommer.

Excerpted from Wikipedia’s “thulium” article, available under the CC BY-SA 4.0 licence.