Page 17 - Academic Press Encyclopedia of Physical Science and Technology 3rd InOrganic Chemistry

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Encyclopedia of Physical Science and Technology EN001F-11 May 7, 2001 12:19

Actinide Elements 225

TABLE VIII Stability of Actinide Ions in Aqueous Solution
Ion Preparation Stability
Md 2+ Slowly oxidized to Md 3+
No 2+ Stable
Ac 3+ Stable
U 3+ Electrolytic reduction (Zn or Na/Hg on UO) Slowly oxidized by water; rapidly by air to U 4+
Np 3+ Electrolytic reduction (H 2 /Pt) Stable to water; rapidly oxidized by air to Np 4+
P¨u 3+ SO 2 ,NH 2 OH, Zn, U 4+ ,orH 2 (Pt) reduction Stable to water and air; oxidized by its own α
radiation to Pu 4+ (in case of 239 Pu)
Am 3+ Iodide, SO 2 reduction Stable; difficult to oxidize
Cm 3+ Stable
Bk 3+ Stable; can be oxidized to Bk 4+
Cf 3+ Stable
Es 3+ Stable
Fm 3+ Stable
Md 3+ Stable; can be reduced to Md 2+
No 3+ Oxidation of No 2+ with Ce 4+ Easily reduced to No 2+
Lr 3+ Stable
Th 4+ Stable
Pa 4+ Reduction of PaO 2+ in HCl (Zn/Hg, Cr 2+ , or Stable to water; rapidly oxidized by air to Pa(V)
Ti 3+ ); electrolytic reduction
U 4+ Air oxidation of U 3+ ; reduction of UO 2+ (Zn or Stable to water; slowly oxidized by air to UO 2+
H 2 with Ni); electrolytic reduction of UO 2+
−
Np 4+ Air oxidation of Np 3+ ;Fe 2+ ,SO 2 ,I or H 2 (Pt) reduction Stable to water; slowly oxidized by air to NpO +
2
Pu 4+ BrO ,Ce 4+ ,Cr 2 O 2− , HIO 3 ,orMnO oxidation Stable in 6M acids, disproportionates to Pu 3+
−
−
3
4
7
+
−
in acid; HNO 2 ,NH 3 OH ,I ,3M HI, 3M HNO 3 , and PuO at lower acidities
+
2
Fe 2+ ,C 2 O 2− , or HCOOH reduction in acid
4
Am 4+ Electrolytic oxidation of Am 3+ in 12M H 3 PO 4 Not stable in water; stable in 15M NH 4 F CmF 2−
6
◦
Cm 4+ Dissolution of CmF 4 in 15M CsF stable1hat25 C
−
Bk 4+ Cr 2 O 2− or BrO oxidation of Bk 3+ Reasonably stable in solution, easily reduced to Bk 3+
3
7
Cf 3+ Oxidation of Cf 3+ using potassium persulfate, Slowly reduced to Cf 3+
stabilization with phosphotungstate
PaO + 2 Stable; reduction difficult
UO + Electrolytic reduction of UO 2+ ;UO 2+ Greatest stability at pH 2.5; disproportionates to U 4+
2 2 2
reduction by Zn/Hg or H 2 at pH 2.5 and UO 2+
2
NpO + 2 NH 2 NH 2 ,NH 2 OH, HNO 2 ,H 2 O 2 /HNO 3 ,Sn 2+ , Stable; disproportionates only in strong acids
or SO 2 reduction of NpO 2+
2
−
PuO + Reduction of PuO 2+ by I ,Fe 2+ ,V 3+ ,SO 2 ,orU 4+ Most stable at low acidity; disproportionates to Pu 4+ and PuO 2+
2 2 2
AmO + Oxidation of Am 3+ with O 3 ,S 2 O 2− , OCl , Disproportionates in strong acids to Am 3+ and AmO 2+ , reduction to
−
2
2
8
or by electrolysis Am 3+ at low acidities by its own α radiation in case of 241 Am
UO 2+ Stable; difficult to reduce
2
−
NpO 2+ Oxidation of Np 4+ with Ce 4+ , MnO ,Ag 2+ ,Cl 2 , Stable in acidic or complexed solutions
2
4
or BrO −
3
−
PuO 2+ Oxidation of Pu 4+ with BiO ,Ce 4+ ,Ag 2+ Stable, fairly easy to reduce; slow reduction by its
2 3
or a number of other reagents own α radiation
+
AmO 2+ Oxidation of Am 3+ or AmO by S 2 O 2− or Ag 2+ Stable, rapid reduction by its own α radiation
8
2
2
NpO 3− Oxidation of NpO 2+ in alkaline solution by O 3 , Stable only in alkaline solution
5 2
S 2 O 2− , ClO , BrO ,orBiO −
−
−
8 3
PuO 3− Oxidation of PuO 2+ in alkaline solution by O 3 , Stable only in alkaline solution, oxidizes water
2
5
−
S 2 O 2− , ClO ,orBrO −
8
AmO 3− Oxidation of AmO 2+ in alkaline solution by O 3 Stable only in alkaline solution
5
2