Lanthanum-138

Naturally occurring lanthanum (₅₇La) is composed of one stable (¹³⁹La) and one radioactive (¹³⁸La) isotope, with the stable isotope, ¹³⁹La, being the most abundant (99.91% natural abundance). There are 38 radioisotopes that have been characterized, with the most stable being ¹³⁸La, with a half-life of 1.02×10¹¹ years; ¹³⁷La, with a half-life of 60,000 years and ¹⁴⁰La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute.

Spectrum (Fullscreen)

Spectrum of a sample of La-(III)-oxide. 5 minute measurement with a High Purity Germanium (HPGe) radiation detector.

Metadata

Isotope:	Lanthanum
Mass number:	138
Atomic number:	57
Neutron number:	81
…	…

Sources and Further Read

• https://en.wikipedia.org/wiki/Lanthanum#Isotopes
• https://en.wikipedia.org/wiki/Lanthanum_oxide
• https://en.wikipedia.org/wiki/Isotopes_of_lanthanum