Símbolo	Os
Número atómico	76
Grupo	8 (Familia del hierro)
Período	6
Bloque	d
Clasificación	Metal de transición

Apariencia	Silvery, blue cast
Color	Gris Pizarra

Número de protones	76 p+
Número de neutrones	114 n0
Número de electrones	76 e-

De Wikipedia, la enciclopedia libreEl osmio es un elemento químico de número atómico 76 que se encuentra en el grupo 8 de la tabla periódica de los elementos. Su símbolo es Os. Se trata de un metal de transición blanco grisáceo, frágil y sólido. Se clasifica dentro del grupo del platino, y se emplea en algunas aleaciones con platino e iridio. Se encuentra aleado en menas de platino y su tetróxido, OsO₄.​ El osmio es el elemento natural más pesado a igual volumen (es decir, más denso) que existe, con una densidad de 22.59 g/cm³ y masa atómica de 190.23

Fase en STP	Sólido
Densidad	22.59 g/cm3
Peso atómico	190.233 u

Punto de fusión	3306 K 3032.85 °C 5491.13 °F
Punto de ebullición	5285 K 5011.85 °C 9053.33 °F
Entalpía de vaporización	627.6 kJ/mol

Electronegatividad (Escala de Pauling)	2.2
Afinidad electrónica	103.99 kJ/mol
Estado de oxidación	−4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8 (a mildly acidic oxide)
Energía de ionización	840 kJ/mol 1600 kJ/mol

Configuración electrónica Configuración abreviada	[Xe] 4f14 5d6 6s2
Configuración electrónica Configuración completa	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d6 6s2
Carta de configuración de electrones	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d6 6s2
Electrones por nivel	2, 8, 18, 32, 14, 2
Electrones de valencia	2
Electrones de valency	2,3,4
Modelo atómico de Bohr	Figura: Diagrama de capa del átomo de Osmio (Os).
Diagrama orbital 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s

Descubrimiento y primer aislamiento	Smithson Tennant (1803)
Nombrado por	Smithson Tennant
Descubrimiento de osmio Osmium was discovered in 1803 by Smithson Tennant and William Hyde Wollaston in London, England. The discovery of osmium is intertwined with that of platinum and the other metals of the platinum group. Platinum reached Europe as platina ("small silver"), first encountered in the late 17th century in silver mines around the Chocó Department, in Colombia. The discovery that this metal was not an alloy, but a distinct new element, was published in 1748. Chemists who studied platinum dissolved it in aqua regia (a mixture of hydrochloric and nitric acids) to create soluble salts. They always observed a small amount of a dark, insoluble residue. Joseph Louis Proust thought that the residue was graphite. Victor Collet-Descotils, Antoine François, comte de Fourcroy, and Louis Nicolas Vauquelin also observed iridium in the black platinum residue in 1803, but did not obtain enough material for further experiments. In 1803, Smithson Tennant analyzed the insoluble residue and concluded that it must contain a new metal. Vauquelin treated the powder alternately with alkali and acids and obtained a volatile new oxide, which he believed was of this new metal—which he named ptene, from the Greek word πτηνος (ptènos) for winged. However, Tennant, who had the advantage of a much larger amount of residue, continued his research and identified two previously undiscovered elements in the black residue, iridium and osmium. He obtained a yellow solution by reactions with sodium hydroxide at red heat. After acidification he was able to distill the formed OsO4. He named it osmium after Greek osme meaning "a smell", because of the ashy and smoky smell of the volatile osmium tetroxide. Discovery of the new elements was documented in a letter to the Royal Society on June 21, 1804.

CAS Number	7440-04-2
ChemSpider ID	22379
EC number	231-114-0
PubChem CID Number	23937