Tecken | Fe |
Atomnummer | 26 |
Grupp | 8 (Järngruppen) |
Period | 4 |
Block | d |
Ämnesklass | Övergångsmetall |
Utseende | Lustrous metallic with a grayish tinge |
Färg | Grå |
Antal protoner | 26 p+ |
Antal neutroner | 30 n0 |
Antal elektroner | 26 e- |
Fas vid STP | Fast |
Densitet | 7.874 g/cm3 |
Relativ atommassa | 55.8452 u |
Smältpunkt | 1811 K 1537.85 °C 2800.13 °F |
Kokpunkt | 3134 K 2860.85 °C 5181.53 °F |
Ångbildningsvärme | 349.5 kJ/mol |
Elektronegativitet (Paulingskalan) | 1.83 |
Elektronaffinitet | 14.785 kJ/mol |
Oxidationstal | −4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7 (an amphoteric oxide) |
Jonisationspotential |
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Upptäckt | Middle East (5000 f.Kr.) |
Upptäckten av järn There is evidence that iron was known from before 5000 BC. The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the Iron Age around 1200 BC and the prominent use of iron for tools and weapons. However, iron artefacts of great age are much rarer than objects made of gold or silver due to the ease with which iron corrodes. The technology developed slowly, and even after the discovery of smelting it took many centuries for iron to replace bronze as the metal of choice for tools and weapons. |