Protactinium

shiny, malleable metal; readily tarnishes in air; α: tetr, a = 0.3929 nm, c = 0.3241 nm, stable from room temp up to 1170°C; β: bcc, a = 0.381 nm, stable from 1170°C–1575°C; first discovered in 1917; enthalpy of fusion 12.34 kJ/mol; can be produced by nuclear reaction 230Th + n → 231Th + γ 231Th → 231Pa, however, Pa is also found in natural sources; t1/2 231Pa is 3.25 × 10+4 years [KIR78] [MER06] [CRC10]

Protactinium atom is an actinoid atom and a f-block element atom.|A radioactive element of the actinide group of metals. It has the atomic symbol Pa, atomic number 91, and atomic weight 231. It decays by alpha-emission.

233Pa as intermediate in production of fissile 233U in thorium breeder reactors.

Molecular Weight:231.03588
Exact Mass:231.03588
Monoisotopic Mass:231.03588
Heavy Atom Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes