Pm - Promethium

Promethium was found in minerals in 1926 by Harris and Hopkins in the US and independantly by Rolla and Fernando in Italy. Synthetic promethium was produced by H. B. Law in 1941. Promethium is very rare.

Atomic number - 61 Density g/mL 6 .475
Atomic weight u 145 Melting point K 1441
Bonding radius A 1 .63 Boiling point K 2733
Atomic radius A 2 .62 Heat of vaporization kJ/mol -
Ionization Potential V 5 .554 Heat of fusion kJ/mol -
Electronegativity - 1 .13 Specific heat J/gK -
The oxide is mildly basic.
Crystal are hexagonal.

Electron config. : [Xe] 4f5 6s2

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac** Rf Db Sg Bh Hs Mt 110 111 112 113
Lanthanides* Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Actinides ** Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Isotopes of Pm: Click mass number for decay process, product for element page.
130
2.2 sec
EC/ECp,10.900
Nd-130/Pr-129
129.94041 		132
6.3 sec
EC/ECp,9.900
Nd-132/Pr-131
131.93376 		133
15 sec
EC,7.000 MeV
Nd-133
132.92968 		134
5 sec
EC,8.900 MeV
Nd-134
133.92817 		135
45 sec
EC,5.940 MeV
Nd-135
134.92463 		136
107 sec
EC,7.850 MeV
Nd-136
135.92344 		137
2.4 min
EC,5.580 MeV
Nd-137
136.92063
138
10 sec
EC,6.900 MeV
Nd-138
137.91937 		139
4.15 min
EC,4.520 MeV
Nd-139
138.91677 		139a
180 msec
EC,4.709 MeV
Nd-139
138.91698 		140
9.2 sec
EC,6.090 MeV
Nd-140
139.91584 		141
20.90 min
EC,3.715 MeV
Nd-141
140.91359 		142
40.5 sec
EC,4.870 MeV
Nd-142
141.91294 		143
265 da
EC,1.041 MeV
Nd-143
142.91092
144
363 da
EC,2.332 MeV
Nd-144
143.91258 		145
17.7 yr
a/EC,1.805
Pr-141/Nd-145
144.91274 		146
5.53 yr
B-/EC,1.472
Sm-146/Nd-146
145.91469 		147
2.6234 yr
B-,2.690 MeV
Sm-147
146.91513 		148
5.370 da
B-,2.468 MeV
Sm-148
147.91746 		149
53.08 hr
B-,1.071 MeV
Sm-149
148.91833 		150
2.68 hr
B-,3.454 MeV
Sm-150
149.92097
151
28.40 hr
B-,1.187 MeV
Sm-151
150.92120 		152
4.12 min
B-,3.500 MeV
Sm-152
151.92348 		153
5.4 min
B-,1.900 MeV
Sm-153
152.92413 		154
1.73 min
B-,4.050 MeV
Sm-154
153.92655 		155
41.5 sec
B-,3.170 MeV
Sm-155
154.92804 		156
26.70 sec
B-,5.160 MeV
Sm-156
155.93105 		157
10.56 sec
B-,4.500 MeV
Sm-157
156.93322
158
4.8 sec
B-,6.200 MeV
Sm-158
157.93666 		MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass

Updated by clh on 2/6/98. This is not a publication of Phoenix College.