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Osmium (Os)

engelsk: Osmium
Osmium er et kemisk grundstof i det periodiske system med kemisk symbol Os og atomnummer 76 med en atomvægt på 190.233 u og er klassificeret som overgangsmetal og er en del af gruppen 8 (jerngruppe). Osmium er fast ved stuetemperatur.

Osmium i det periodiske system

SymbolOs
Atomnummer76
Gruppe8 (Jerngruppe)
Periode6
Blokd
KlassifikationOvergangsmetal
UdseendeSilvery, blue cast
Farve Skifergrå
Antal protoner76 p+
Antal neutroner114 n0
Antal elektroner76 e-
Fra Wikipedia, den gratis encyklopædiOsmium (af ὀσμή, osme, græsk for "en lugt") er det 76. grundstof i det periodiske system, og har det kemiske symbol Os: Under normale tryk- og temperaturforhold optræder dette overgangsmetal som et skinnende, let blåligt, og ekstremt tungt og hårdt metal. Osmium udgør sammen med iridium og platin de tunge platinmetaller.

Fysiske egenskaber

Fase ved STPFast
Massefylde22.59 g/cm3
Atommasse190.233 u

Thermal properties

Smeltepunkt3306 K
3032.85 °C
5491.13 °F
Kogepunkt5285 K
5011.85 °C
9053.33 °F
Fordampningsvarme627.6 kJ/mol

Atomiske egenskaber

Elektronegativitet (Pauling Scale)2.2
Elektronaffinitet103.99 kJ/mol
Oxidationstrin−4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8
(a mildly acidic oxide)
Ioniseringsenergier
  1. 840 kJ/mol
  2. 1600 kJ/mol

Elektronkonfiguration for osmium

Elektronkonfiguration
Kortfattet konfiguration
[Xe] 4f14 5d6 6s2
Elektronkonfiguration
Fuld konfiguration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d6 6s2
Elektronkonfigurationsdiagram
1s2
2s22p6
3s23p63d10
4s24p64d104f14
5s25p65d6
6s2
Elektroner pr. Skal2, 8, 18, 32, 14, 2
Valenselektroner 2
Valency-elektroner 2,3,4
Bohrs atommodel
OsmiumElectron shell for Osmium, created by Injosoft ABOs
Figur: Skaldiagram af Osmium (Os) atom.
Orbital diagram
1s
2s2p
3s3p3d
4s4p4d4f
5s5p5d
6s

The history of Osmium

Opdagelse og første isolationSmithson Tennant (1803)
Navngivet afSmithson Tennant
Opdagelse af osmium
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.

Identifikatorer

List of unique identifiers for Osmium in various chemical registry databases
CAS Number7440-04-2
ChemSpider ID22379
EC number231-114-0
PubChem CID Number23937