Platinum
Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name is derived from the Spanish term "platino", meaning "little silver".
Platinum
Platinum has six naturally occurring isotopes: Pt, Pt, Pt, Pt, Pt, and Pt. The most abundant of these is Pt, comprising 33.83% of all platinum. It is the only stable isotope with a non-zero spin; with a spin of /, Pt satellite peaks are often observed in H and P NMR spectroscopy (i.e., Pt-phosphine and Pt-alkyl complexes). Pt is the least abundant at only 0.01%. Of the naturally occurring isotopes, only Pt is unstable, though it decays with a half-life of 6.5 years, causing an activity of 15 Bq/kg of natural platinum. Pt can undergo alpha decay, but its decay has never been observed (the half-life is known to be longer than 3.2 years); therefore, it is considered stable. Platinum also has 31 synthetic isotopes ranging in atomic mass from 166 to 204, making the total number of known isotopes 39. The least stable of these is Pt, with a half-life of 300 µs, whereas the most stable is Pt with a half-life of 50 years. Most platinum isotopes decay by some combination of beta decay and alpha decay. Pt, Pt, and Pt decay primarily by electron capture. Pt and Pt are predicted to have energetically favorable double beta decay paths.