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

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

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

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