76
Os
190.233
Osmium
Engelska: Osmium
Övergångsmetall
Grupp 8
Period 6
Block d
Osmium är ett kemiskt grundämne i det periodiska systemet med kemisk beteckningen Os och atomnummer 76 med en atomvikt på 190.233 u och klassas som övergångsmetall och ingår i grupp 8 (järngruppen). Osmium är fast vid rumstemperatur.
Osmium i det periodiska systemet
| Tecken | Os |
| Atomnummer | 76 |
| Grupp | 8 (Järngruppen) |
| Period | 6 |
| Block | d |
| Ämnesklass | Övergångsmetall |
| Utseende | Silvery, blue cast |
| Färg | Skiffer grå |
| Antal protoner | 76 p+ |
| Antal neutroner | 114 n0 |
| Antal elektroner | 76 e- |
Från Wikipedia, den fria encyklopedinOsmium är ett metalliskt grundämne som tillhör gruppen tunga platinametaller. Det används som katalysator och i legeringar. Ämnet upptäcktes 1804 av den engelske kemisten Tennant.
Fysikaliska egenskaper
| Fas vid STP | Fast |
| Densitet | 22.59 g/cm3 |
| Relativ atommassa | 190.233 u |
Thermal properties
| Smältpunkt | 3306 K 3032.85 °C 5491.13 °F |
| Kokpunkt | 5285 K 5011.85 °C 9053.33 °F |
| Ångbildningsvärme | 627.6 kJ/mol |
Atomära egenskaper
| Elektronegativitet (Paulingskalan) | 2.2 |
| Elektronaffinitet | 103.99 kJ/mol |
| Oxidationstal | −4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8 (a mildly acidic oxide) |
| Jonisationspotential |
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Elektronkonfiguration för osmium
Elektronkonfiguration Kortfattad konfiguration | [Xe] 4f14 5d6 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Full konfiguration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d6 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elektronkonfigurationsdiagram |
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| Elektroner per skal | 2, 8, 18, 32, 14, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valence electrons (incl. d) | 8 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valency-elektroner | 2,3,4 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bohrs atommodell | Figur: Skaldiagram över Osmium (Os) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Orbitaldiagram
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The history of Osmium
| Upptäckt och första isolation | Smithson Tennant (1803) |
| Namngivare | Smithson Tennant |
Upptäckten av 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. | |
| Original word | osme |
| Language of origin | Greek |
| Name source | Egenskaper |
| Meaning | “Smell” |
Naming The name is derived from the Greek 'osme', meaning smell, after the strong odour of osmium tetroxide formed when the metal is exposed to air. | |