# Haearn

Haearn|  |
| Enghraifft o: | elfen gemegol, metel  |
| Math | meddyginiaeth, primary metabolite  |
| Màs | 55.845 ±0.002 uned Dalton  |
| Fformiwla gemegol | Fe  |
| Clefydau i'w trin | Iron deficiency anemia, hypochromic anemia  |
| Dyddiad darganfod | c. Mileniwm 5. CC  |
| Symbol | Fe  |
| Rhif atomig | 26  |
| Trefn yr electronnau | [Ar] 3d⁶ 4s²  |
| Electronegatifedd | 1.83  |
| Cyflwr ocsidiad | 1.83  |
| Rhan o | elfen cyfnod 4, Elfen Grŵp 8  |
| Dynodwyr |
| SMILES | [fe]  |
| Freebase | /M/025rw19  |
| Thesawrws y BNCF | 474  |
| CAS | 7439-89-6  |
| PubChem CID | 23925  |
| ChEBI | 18248, 82664  |
| InChI | Inchi=1s/fe  |
| ChemSpider | 22368  |
| UNII | E1uol152h7  |
| Rhif EC | 231-096-4  |
| Drugbank | Db01592  |
| ECHA | 100.028.270  |
| RxNorm CUI | 90176  |
| UMLS CUI | C0302583  |
| NDF-RT | N0000146032  |
|  Ffeiliau perthnasol ar Gomin Wicimedia |

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| Haearn

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| Haearn mewn cynhwysydd |

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| Symbol | Fe |
|  Rhif | 26 |
| Dwysedd | 7874 kg m-3 |

Metel o liw llwyd yw **haearn**, sy'n elfen gemegol yn y tabl cyfnodol ac iddo'r symbol `**Fe**` (o'r Lladin *ferrum* 'haearn') a'r rhif 26. Elfen chweched gyffredinaf y bydysawd ydyw, sy'n bodoli mewn pedwar isotop sefydlog: 54Fe (5.845%), 56Fe (91.754%), 57Fe (2.119%), a 58Fe (0.282%).

Metel ydyw, ond anaml y'i ceir mewn ffurf fetelig ar wyneb y ddaear, gan ei fod yn ocsideiddio ym mhresenoldeb ocsigen a gwlybwr. Defnyddir y mwyn hematit (Fe2O3) yn amlaf i gynhyrchu haearn. Gall priodweddau haearn eu newid gan greu aloion ohono gydag amryw o fetelau eraill (a rhai an-fetelau, yn enwedig carbon a silicon) i ffurfio duroedd.

Taflen hysbysu pobl o siop haearn (*ironmongers*) yn Llannon. Awst 1848
Mae haearn yn rhan anhepgor o ddeiet achos y'i ddefnyddir i ffurfio hemoglobin yn y gwaed. Serch hynny, gall gormodedd o haearn fod yn wenwynig ac mae'n un o'r achosion tocsicolegol cyffredinaf o farwolaeth plant dan 6 oed.

## Gweler hefyd

* Oes yr Haearn
* Dur
* Haearn bwrw
* Haearn smwddio
* Diwydiant haearn Cymru

## Dolenni allanol

* Hanes smeltio haearn

Wiciadur
Chwiliwch am haearn
yn Wiciadur.

 *Eginyn erthygl sydd uchod am **gemeg**. Gallwch helpu Wicipedia drwy ychwanegu ato.*