samarium
/səˈmɛːrɪəm
/noun [mass noun]
The chemical element of atomic number 62, a hard silvery-white metal of the lanthanide series. (Symbol: Sm) For undergraduate chemistry it was required that one could recite the whole thing from memory, to know that iridium lies at the foot of cobalt, that europium is sandwiched between samarium and gadolinium....
- The periodic chart developed by Russian chemist Dmitri Mendeleev showed that an element should be found between neodymium and samarium.
- Many other pairs of isotopes linked by decay processes with long half-lives are used for geological dating of rocks, including samarium - 147 neodymium - 143, rubidium - 87 strontium - 87, and potassium - 40 argon - 40.
Origin
Late 19th century: from samar(skite), a mineral in which its spectrum was first observed (named after Samarsky, a 19th-century Russian official) + -ium.