Mendeleev's Periodic Table > Pr - Praseodymium

Pr - Praseodymium

Baron von Welsbach separated the components of dydimium into neodymium (the new twin) and praseodymium (the green twin) in 1885 in Vienna. Praseodymium is soft, silvery, malleable, and ductile. It was prepared in relatively pure form in 1931. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that "spalls" away when exposed to air. The metal should be stored under an inert atmosphere or under mineral oil or petroleum.

Atomic number	-	59		Density	g/mL	6	.77
Atomic weight	u	140	.9077	Melting point	K	1204
Bonding radius	A	1	.65	Boiling point	K	3785
Atomic radius	A	2	.67	Heat of vaporization	kJ/mol	296	.8
Ionization Potential	V	5	.46	Heat of fusion	kJ/mol	6	.89
Electronegativity	-	1	.13	Specific heat	J/gK	0	.19
The oxide is mildly basic.				Crystal are hexagonal.
Electron config. : [Xe] 4f³ 6s²

Isotopes of Pr (Praseodymium):

MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	121 1.4 sec EC,7.900 MeV Ce-121 120.95400	124 1.2 sec EC/ECp,11.700 Ce-124/La-123 123.94310	126 3.1 sec EC/ECp,10.400 Ce-126/La-125 125.93526	127 4.9 sec EC,7.500 MeV Ce-127 126.93086
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	128 3.1 sec EC/ECp,9.300 Ce-128/La-127 127.92882	129 30 sec EC,6.300 MeV Ce-129 128.92485	130 40.0 sec EC,8.100 MeV Ce-130 129.92334	131 1.53 min EC,5.250 MeV Ce-131 130.92002
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	132 1.6 min EC,7.100 MeV Ce-132 131.91911	133 6.5 min EC,4.300 MeV Ce-133 132.91619	134 17 min EC,6.200 MeV Ce-134 133.91569	135 24 min EC,3.720 MeV Ce-135 134.91313
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	136 13.1 min EC,5.126 MeV Ce-136 135.91264	137 1.28 hr EC,2.702 MeV Ce-137 136.91068	138 1.45 min EC,4.437 MeV Ce-138 137.91074	139 4.41 hr EC,2.129 MeV Ce-139 138.90893
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	140 3.39 min EC,3.388 MeV Ce-140 139.90907	141 100% Stable 140.90764	142 19.12 hr B-/EC,2.162 Nd-142/Ce-142 141.91004	143 13.57 da B-,1.462 MeV Nd-143 142.91081
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	144 17.28 min B-,2.997 MeV Nd-144 143.91330	145 5.984 hr B-,1.805 MeV Nd-145 144.91450	146 24.15 min B-,4.200 MeV Nd-146 145.91761	147 13.4 min B-,2.690 MeV Nd-147 146.91897
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	148 2.27 min B-,4.930 MeV Nd-148 147.92217	149 2.26 min B-,3.397 MeV Nd-149 148.92379	150 6.19 sec B-,5.690 MeV Nd-150 149.92699	151 18.90 sec B-,4.100 MeV Nd-151 150.92822
MASS abundancy Halflife Particle, Energy Decay Product(s) Isotopic Mass	152 3.63 sec B-,6.400 MeV Nd-152 151.93161	153 4.3 sec B-,5.500 MeV Nd-153 152.93397	154 2.3 sec B-,7.900 MeV Nd-154 153.93805

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