What rare earth metal is commonly used in household smoke detectors?

looney_tunes

Americium, specifically the isotope Am-241. http://en.wikipedia.org/wiki/Americium#Ionization_detectors Mar 16 11, 10:30 PM

davejacobs

http://en.wikipedia.org/wiki/Rare_earth_element This site lists all seventeen rare earth elements, but Americium is not one of them. Nor is a smoke detector listed as an application of any of them. Rare earth elements or rare earth metals are a collection of seventeen chemical elements in the periodic table, specifically the fifteen lanthanoids plus scandium and yttrium. Mar 17 11, 1:36 AM

looney_tunes

From the site linked above: "The name americium (after the Americas) and the symbol Am are suggested for the element on the basis of its position as the sixth member of the actinide rare-earth series, analogous to europium, Eu, of the lanthanide series." None of the proper rare earth elements are used in smoke detectors, so this tangential definition gives the best answer I could find to the question, which may have been based on slightly erroneous information. Mar 17 11, 2:11 AM

CliftonClowers

You are both correct. Americium is the element I had in mind when I composed the question and it is of course not a rare earth metal but a transuranic metal. This is what you get when you let an old organic chemist with a faulty memory compose questions about the bottom of the periodic table. Mar 22 11, 10:19 AM