Mendeleev's Periodic Table > Pm - Promethium

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. Great care is required while handling Promethium as a consequence of its radioactivity. Promethium salts luminesce in the dark with a pale blue or greenish glow, due to their high radioactivity. Ion-exchange methods led to the preparation of about 10 grams of promethium from atomic reactor fuel processing wastes in early 1963. Little is yet generally known about the properties of metallic promethium. More than 30 Promethium compounds have been prepared. Promethium is a rare earth metal.

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 (Promethium):

MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	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
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	158 4.8 sec B-,6.200 MeV Sm-158 157.93666

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