Ir - Iridium

This precious transition metal was discovered by Tennant in 1803 in England. Our students don't encounter iridium in the flesh but appears as an answer to a lab question.

Atomic number - 77 Density g/mL 22 .5

Atomic weight u 192 .22 Melting point K 2716

Bonding radius A 1 .27 Boiling point K 4701

Atomic radius A 1 .87 Heat of vaporization kJ/mol 604

Ionization Potential V 9 .1 Heat of fusion kJ/mol 26 .1

Electronegativity - 2 .2 Specific heat J/gK 0 .13

The oxide is mildly basic.
Crystal are face centered cubic.

Electron config. : [Xe] 4f¹⁴ 5d⁷ 6s²

Isotopes of Ir: Click mass number for decay process, product for element page.

166 5 msec a,6.700 MeV Re-162 165.98550	167 5 msec a/p,6.540 MeV Re-163/Os-166 166.98164	168 a,6.410 MeV Re-164 167.97992	169 0.4 sec a/EC/p,6.280 Re-165/Os-169/Os-168 168.97639	170 1.05 sec a/EC,6.170 Re-166/Os-170 169.97502	171 1.5 sec a/EC/p,6.159 Re-167/Os-171/Os-170 170.97180	172 4.4 sec a/EC,9.800 Re-168/Os-172 171.97069
173 9.0 sec a/EC,7.400 Re-169/Os-173 172.96770	174 9 sec a/EC,9.000 Re-170/Os-174 173.96682	175 9 sec a/EC,6.600 Re-171/Os-175 174.96414	176 8 sec a/EC,8.000 Re-172/Os-176 175.96349	177 30 sec a/EC,5.700 Re-173/Os-177 176.96113	178 12 sec EC,7.200 MeV Os-178 177.96103	179 79 sec EC,4.900 MeV Os-179 178.95909
180 1.5 min EC,6.400 MeV Os-180 179.95920	181 4.90 min EC,4.070 MeV Os-181 180.95757	182 15 min EC,5.610 MeV Os-182 181.95820	183 57 min EC,3.450 MeV Os-183 182.95681	184 3.09 hr EC,4.600 MeV Os-184 183.95738	185 14.4 hr EC,2.370 MeV Os-185 184.95658	186 16.64 hr EC,3.831 MeV Os-186 185.95795
187 10.5 hr EC,1.502 MeV Os-187 186.95736	188 41.5 hr EC,2.809 MeV Os-188 187.95885	189 13.2 da EC,1.009 MeV Os-189 188.95871	190 11.78 da EC,2.000 MeV Os-190 189.96059	191 37.3% Stable 190.96059	192 73.830 da B-/EC,1.460 Pt-192/Os-192 191.96260	192a 1.45 min B-,1.517 MeV Pt-192 191.96266
193 62.7% Stable 192.96292	194 19.28 hr B-,7.100 MeV Pt-194 193.96507	195 2.5 hr B-,1.120 MeV Pt-195 194.96597	196 52 sec B-,3.210 MeV Pt-196 195.96838	196a 1.40 hr B-,3.620 MeV Pt-196 195.96882	197 5.8 min B-,2.155 MeV Pt-197 196.96963	198 8 sec B-,4.100 MeV Pt-198 197.97228
MASS abund. Halflife Particle, Energy Decay Product(s) Isotopic Mass

Atomic number	-	77		Density	g/mL	22	.5
Atomic weight	u	192	.22	Melting point	K	2716
Bonding radius	A	1	.27	Boiling point	K	4701
Atomic radius	A	1	.87	Heat of vaporization	kJ/mol	604
Ionization Potential	V	9	.1	Heat of fusion	kJ/mol	26	.1
Electronegativity	-	2	.2	Specific heat	J/gK	0	.13
The oxide is mildly basic.				Crystal are face centered cubic.
Electron config. : [Xe] 4f¹⁴ 5d⁷ 6s²