# Galiwm

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| Galiwm

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| Galiwm mewn cynhwysydd |

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| Symbol | Ga |
|  Rhif | 31 |
| Dwysedd | 5.91  g·cm−3 |

Galiwm|  |
| Enghraifft o: | elfen gemegol, elfen chalcophile  |
| Math | post-transition metal  |
| Deunydd | gallite, bauxite, zinc ore  |
| Màs | 69.723 ±0.001 uned Dalton  |
| Fformiwla gemegol | Ga  |
| Dyddiad darganfod | 1875  |
| Symbol | Ga  |
| Rhif atomig | 31  |
| Electronegatifedd | 1.81  |
| Cyflwr ocsidiad | 1.81  |
| Rhan o | elfen cyfnod 4, Elfen Grŵp 13  |
| Dynodwyr |
| SMILES | [ga]  |
| Freebase | /M/025rs35  |
| CAS | 7440-55-3  |
| PubChem CID | 5360835  |
| ChEBI | 49631  |
| InChI | Inchi=1s/ga  |
| ChemSpider | 4514603  |
| UNII | Ch46oc8yv4  |
| Rhif EC | 231-163-8  |
| ECHA | 100.028.330  |
| RxNorm CUI | 1310124  |
|  Ffeiliau perthnasol ar Gomin Wicimedia |

Elfen gemegol yn y tabl cyfnodol yw **galiwm** gyda'r symbol `**Ga**` a'r rhif atomig 31. Mae'n fetel ôl-drosiannol sgleiniog, meddal ac arianaidd. Mae ganddo ymdoddbwynt isel am fetel, ac mae'r metel yn ymdoddi yn y llaw. Mae galiwm yn ffurfio nifer sylweddol o gyfansoddion yn cynnwys galiwm arsenid, sy'n ddeunydd defnyddiol ar gyfer deuodau allyrru golau ac yn y diwidiant electroneg.

## Hanes

Yn 1875 darganfuwyd galiwm (Lladin *Gallia* am ardal Gâl) gan Clemens Winkler. Un o'r elfennau a ragwelodd Dmitri Mendeleev oedd galiwm i lenwi bylchau yn ei dabl cyfnodol. Gan ei fod o dan alwminiwm yn y tabl, fe enwodd yr elfen yn eka-alwminiwm ac roedd canlyniadau'r astudiaethau o'r elfen newydd yn un o'r camau pwysicaf yn y llwybr i brofi pwysigrwydd y tabl cyfnodol a chyfnodedd.

| Priodwedd | Eka-alwminiwm | Galiwm |
| --- | --- | --- |
| Mas cymharol | tua 68 | 69.7 |
| Dwysedd(g/cm3) | 6.0 | 5.91 |
| Ymdoddbwynt (°C) | isel | 29.8 |

## Dolenni allanol

* Los Alamos National Laboratory – Galiwm Archifwyd 2008-06-10 yn y Peiriant Wayback
* WebElements.com – Galiwm