Os - Osmium

A precious metal. Osmium is used in ball pens, as a forensic stain, and in electronic applications. Discovered in 1804 by Englishman Smithson Tennent in the residue left by dissolving platinum in aqua regia. A comprehensive guide to the simple chemistry of the metal can be found in The Chemistry of the Rarer Platinum Metals (John Wiley, New York, 1967).

Powdered osmium is oxidized in air at room temperature to form highly toxic osmium tetroxide. Found naturally with iridium, paladium, rhodium and platinum.

Atomic number - 76 Density g/mL 22 .4

Atomic weight u 190 .2 Melting point K 3300

Bonding radius A 1 .26 Boiling point K 5285

Atomic radius A 1 .92 Heat of vaporization kJ/mol 746

Ionization Potential V 8 .7 Heat of fusion kJ/mol 31 .8

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

The oxide is mildly acidic.
Crystal are hexagonal.

Electron config. : [Xe] 4f¹⁴ 5d⁶ 6s²

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

162 1.9 msec a,6.780 MeV W-158 161.98378	163 a/EC,9.400 W-159/Re-163 162.98207	164 41 msec a/EC,6.478 W-160/Re-164 163.97788	165 73 msec a/EC,6.320 W-161/Re-165 164.97648	166 194 msec a/EC,6.131 W-162/Re-166 165.97252	167 0.83 sec a/EC,5.980 W-163/Re-167 166.97133	168 2.2 sec a/EC,5.700 W-164/Re-168 167.96775
169 3.4 sec a/EC,7.680 W-165/Re-169 168.96707	170 7.3 sec a/EC,5.000 W-166/Re-170 169.96356	171 8.0 sec a/EC,7.100 W-167/Re-171 170.96307	172 19.2 sec a/EC,4.500 W-168/Re-172 171.96007	173 16 sec a/EC,6.300 W-169/Re-173 172.95974	174 44 sec a/EC,3.700 W-170/Re-174 173.95716	175 1.4 min EC,5.300 MeV Re-175 174.95705
176 3.6 min EC,3.200 MeV Re-176 175.95496	177 2.8 min EC,4.500 MeV Re-177 176.95512	178 5.0 min EC,2.300 MeV Re-178 177.95335	179 6.5 min EC,3.680 MeV Re-179 178.95393	180 21.5 min EC,1.470 MeV Re-180 179.95235	181 105 min EC,2.930 MeV Re-181 180.95321	182 22.10 hr EC,2.800 MeV Re-182 181.95218
183 13.0 hr EC,2.130 MeV Re-183 182.95310	184 0.020% 5.6E13 yr ,1.671 MeV 183.95249	185 93.6 da EC,1.013 MeV Re-185 184.95404	186 1.58% 2.0E+15 yr a,2.822 MeV W-182 185.95383	187 1.6% Stable 186.95574	188 13.3% Stable 187.95583	189 16.1% Stable 188.95814
190 26.4% Stable 189.95844	191 15.4 da B-,2.045 MeV Ir-191 190.96092	192 41.0% B-Stable Ir-192 191.96147	193 30.5 hr B-,1.140 MeV Ir-193 192.96414	194 6.0 yr B-,7.100 MeV Ir-194 193.96517	195 6.5 min B-,2.000 MeV Ir-195 194.96811	196 34.9 min B-,1.160 MeV Ir-196 195.96961
MASS abund. Halflife Particle, Energy Decay Product(s) Isotopic Mass

Atomic number	-	76		Density	g/mL	22	.4
Atomic weight	u	190	.2	Melting point	K	3300
Bonding radius	A	1	.26	Boiling point	K	5285
Atomic radius	A	1	.92	Heat of vaporization	kJ/mol	746
Ionization Potential	V	8	.7	Heat of fusion	kJ/mol	31	.8
Electronegativity	-	2	.2	Specific heat	J/gK	0	.13
The oxide is mildly acidic.				Crystal are hexagonal.
Electron config. : [Xe] 4f¹⁴ 5d⁶ 6s²