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Properties of substance:

protoactinium

Group of substances:

inorganic

Physical appearance:

metal

Empirical formula (Hill's system for organic substances):

Pa

Structural formula as text:

Pa

Molar/atomic mass: 231.0359

Melting point (°C):

1572

Boiling point (°C):

4487

Numerical data:

Year of discovery: 1917
Superconducting temperature (K): 1.4

Density:

15.37 (20°C, g/cm3)

Half-life:

21291Pa = 7.5 ms (α (100%))
21391Pa = 7 ms (α (100%))
21491Pa = 17 ms (α (about 100%))
21591Pa = 14 ms (α (100%))
21691Pa = 105 ms ()
21791Pa = 3.48 ms (α (100%))
217m91Pa = 1.08 ms (α (73%))
21891Pa = 113 μs (α (100%))
21991Pa = 53 ns (α (100%))
22091Pa = 780 ns (α (100%))
22191Pa = 5.9 μs (α (100%))
22291Pa = 3.2 ms (α (100%))
22391Pa = 5.2 ms (α (100%))
22491Pa = 846 ms (α (about 100%))
22591Pa = 1.7 s (α (100%))
22691Pa = 1.8 min (α (74%), β+ (26%))
22791Pa = 38.3 min (α (85%), electron capture (15%))
22891Pa = 22 h (β+ (98.15%), α (1.85%))
22991Pa = 1.50 d (electron capture (about 100%), α (0.48%))
23091Pa = 17.4 d (β+ (92.2%), β- (7.8%), α (0.0032%))
23191Pa = 32 760 y (α (100%), spontaneous fission. heavy cluster emission 24Ne)
23291Pa = 1.32 d (β- (about 100%), electron capture (0.003%))
23391Pa = 26.975 d (β- (100%))
23491Pa = 6.70 h (β- (100%), spontaneous fission)
23591Pa = 24.4 min (β- (100%))
23691Pa = 9.1 min (β- (100%), spontaneous fission (6·10-8%))
23791Pa = 8.7 min (β- (100%))
23891Pa = 2.28 min (β- (100%))
23991Pa = 1.8 h (β- (100%))

Molar enthalpy (heat) of fusion ΔfusH (kJ/mol):

16.7

Enthalpy (heat) of vaporization ΔvapH (kJ/mol):

481

References:

  1. Гринвуд Н., Эрншо А. Химия элементов. - Т.2. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 580 [Russian]
  2. Пальшин Е.С., Мясоедов Б.Ф., Давыдов А.В. Аналитическая химия протактиния. - М.: Наука, 1968. - pp. 16-17 [Russian]
  3. Успехи химии. - 1960. - Т.29, №7. - pp. 882-898 [Russian]
  4. Успехи химии. - 1966. - Т.35, №3. - pp. 460-486 [Russian]
  5. Химическая энциклопедия. - Т. 4. - М.: Советская энциклопедия, 1995. - pp. 111 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru