# Lithiwm

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|

|  |
| --- |
| helium ← **lithium** → beryllium |
| H ↑ **Li** ↓ Na
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**3Li**
Y Tabl Cyfnodol |

 |

 |
| Ymddangosiad
 |
| arian golau (Fe'i gwelir yma'n arnofio mewn olew)   Llinellau sbectral lithiwm
 |
| Nodweddion cyffredinol
 |
| Enw, symbol, rhif
 | lithium, Li, 3
 |
| Ynganiad
 | /ˈlɪθiəm/ LI**-thee-əm* |
| Teulu'r elfennau
 | Metel alcalïaidd
 |
| Grŵp, cyfnod, bloc
 | 1, 2, s
 |
| Rhif atomig
 | 6.941(2)
 |
| Patrwm yr Electronnau
 | 1s2 2s1 or [He]2s1 |
| Electronnau / cragen
 | 2, 1 (Image)
 |
| Nodweddion ffisegol
 |
| Stâd
 | solid
 |
| Dwysedd (oddeutu tymheredd yr ystafell)
 | 0.534 g·cm−3 |
| Dwysedd hylif / Ymdoddbwynt
 | 0.512 g·cm−3 |
| Ymdoddbwynt
 | 453.69 K, 180.54 °C, 356.97 °F
 |
| Berwbwynt
 | 1615 K, 1342 °C, 2448 °F
 |
| Pwynt critigol
 | (extrapolated) 3223 K, 67 MPa
 |
| Enthalpi ymdoddiad
Gwres o ymdoddi

 | {{{heat fusion 2}}} kJ·mol−1 |
| Enthalpi anweddiad

 | Vapor pressure
 |
|

|  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| P (Pa)
 | 1
 | 10
 | 100
 | 1 k
 | 10 k
 | 100 k
 |
| at T (K)
 | 797
 | 885
 | 995
 | 1144
 | 1337
 | 1610
 |

 |
| Nodweddion Atomig
 |
| cyflwr ocsidiad
 | **+1**, -1 (strongly basic oxide)
 |
| Electronegativity
 | 0.98 (Graddfa Pauling)
 |
| Ionization energies
 | 1st: 520.2 kJ·mol−1 |
| 2: 7298.1 kJ·mol−1 |
| 3ydd: 11815.0 kJ·mol−1 |
| Radiws atomig
 | 152 pm
 |
| Radiws cofalent
 | 128±7 pm
 |
| Radiws Van der Waals
 | 182 pm
 |
| Amrywiol
 |
| Strwythyr y crisal
 | body-centered cubic
 |
| Magnetic ordering
 | paramagnetic
 |
| Gwrthedd trydanol
 | (20 °C) 92.8 nΩ·m
 |
| Dargludiad Thermal
 | 84.8 W·m−1·K−1 |
| Ehangiad thermal
 | (25 °C) 46 µm·m−1·K−1 |
| Cyflymder sain
 | (20 °C) 6000 m·s−1 |
| Modwlws Young
 | 4.9 GPa
 |
| Modwlws Shear
 | 4.2 GPa
 |
| Modwlws Bulk
 | 11 GPa
 |
| Graddfa caledwch Mohs
 | 0.6
 |
| CAS registry number
 | 7439-93-2
 |
| Most stable isotopes
 |
| Main article: Isotopes of lithium
 |
|

| iso
 | NA
 | half-life
 | DM
 | DE (MeV) | DP
 |
| --- | --- | --- | --- | --- | --- |
| 6Li
 | 7.5%
 | 6Li is stable with 3 neutrons
 |
| 7Li
 | 92.5%
 | 7Li is stable with 4 neutrons
 |
| 6Li content may be as low as 3.75% in natural samples. 7Li would therefore have a content of up to 96.25%.
 |

 |
| * v
* t
* e
 |

Lithiwm battery
Metel alcalïaidd gwyn eithaf meddal yw **lithiwm** (tarddiad: Groeg: λίθος *lithos*, "carreg"); mae'n elfen gemegol yn y tabl cyfnodol ac fe'i gynrychiolir gan y symbol `**Li**` a'r rhif atomig 3. Dyma'r metel ysgafnaf ac fel pob un o'r grwp mae'n adweithio'n sydyn ac mae'n fflamadwy iawn. Oherwydd hyn, caiff ei storio fel arfer mewn olew. Pan gaiff ei dorri, mae'n lliw metalig, ond mae'r lliw'n pylu'n sydyn pan ddaw i gyffyrddiad gyda'r aer o'i gwmpas, gan droi'n ddu.

Oherwydd ei adweithiad uchel, nid yw ar gael mewn ffurf naturiol ar y blaned, dim ond mewn yn rhan o gymysgedd o fetalau eraill, a'r rheiny fel arfer yn eionig. Fe'i ceir hefyd yn nŵr y môr a gellir ei gynaeafu ohono ac o glai. Mewn diwydiant defnyddir electrolysis i'w insiwleiddio (ei wahanu) oddi wrth cymysgedd o lithiwm clorid a potasiwm clorid.

Defnyddir tri chwarter y lithiwm a gynhyrchir yn fydeang ar gyfer batris lithiwm a batri lithiwm-ion. Defnyddir y rhain yn gynyddol i yrru ceir trydan fel rhai Tesla, ffonau clyfar a thabledi digidol. Mae un o'r chwareli mwyaf sy'n echdynnu'r metalau o'r ddaear yng Ngogledd Mecsico.

Wiciadur
Chwiliwch am lithiwm
yn Wiciadur.