Thallium

Thallium

Thallium is a chemical element. It has the chemical symbol Tl. It has the atomic number 81. Its standard atomic weight is 204.4. It is found in Group 15 of the periodic table. Thallium is a gray metal that is very toxic.

Properties

Physical properties

Thallium is a soft, malleable, grayish post-transition metal. It can be cut with a knife at room temperature. It melts at a low temperature, 304°C. This is typical of a post-transition metal. Thallium has 25 isotopes and two stable (nonradioactive) ones. It is extremely toxic.

Chemical properties

A corroded thallium rod

Thallium is a moderately reactive metal. It corrodes easily in air with a blue-gray color that is similar to lead. If it is kept in air for a long time, a large amount of thallium(I) oxide will build up. It corrodes in the presence of water to make the hydroxide. It burns with a greenish flame. It reacts with most acids.

Chemical compounds

Thallium makes chemical compounds in two oxidation states: +1 and +3. The +1 state is more common and less reactive. Its chemical compounds are very similar to potassium or silver compounds. It makes a hydroxide that in a strong base when dissolved in water. Most other transition metal and post-tranansition metal hydroxides do not dissolve in water. This reacts with carbon dioxide to make thallium(I) carbonate, which is also water-soluble and very heavy. It is the only heavy metal carbonate that can dissolve in water. Other compounds are similar to silver compounds. Thallium(I) bromide turns yellow when exposed to light, similar to silver(I) bromide. Thallium(I) sulfide is black, similar to silver(I) sulfide. The +3 state compounds are oxidizing agents. The black oxide, thallium(III) oxide and the hydroxide, thallium(III) hydroxide, are the only stable +3 compounds. They break down to oxygen and thallium(I) oxide when heated. Thallium and its compounds are rare because they are toxic and polluting.

Thallium(I) chloride

+1 compounds

+1 compounds are quite unreactive. It is the more common oxidation state. They are made when thallium dissolves in acids or corrodes in air.

+3 compounds

+3 compounds are oxidizing agents. They are quite rare.

Other Languages
Afrikaans: Tallium
አማርኛ: ታሊየም
العربية: ثاليوم
aragonés: Talio
armãneashti: Taliu
asturianu: Taliu
azərbaycanca: Tallium
Bân-lâm-gú: Thallium
беларуская: Талій
беларуская (тарашкевіца)‎: Таль
भोजपुरी: थैलियम
български: Талий
བོད་ཡིག: བེལ་ལིམ
bosanski: Talij
brezhoneg: Talliom
català: Tal·li
Чӑвашла: Талли
Cebuano: Talyo
čeština: Thallium
corsu: Talliu
Cymraeg: Thaliwm
dansk: Thallium
Deutsch: Thallium
eesti: Tallium
Ελληνικά: Θάλλιο
English: Thallium
español: Talio
Esperanto: Taliumo
euskara: Talio
فارسی: تالیم
Fiji Hindi: Thallium
français: Thallium
furlan: Tali
Gaeilge: Tailliam
Gaelg: Thallium
Gàidhlig: Tailium
galego: Talio
ગુજરાતી: થેલીયમ
客家語/Hak-kâ-ngî: Thallium
хальмг: Таллиум
한국어: 탈륨
հայերեն: Թալիում
हिन्दी: थैलियम
hrvatski: Talij
Ido: Talio
Bahasa Indonesia: Talium
interlingua: Thallium
íslenska: Þallín
italiano: Tallio
עברית: תליום
Kabɩyɛ: Taalɩyɔm
ಕನ್ನಡ: ಥಾಲಿಯಮ್
ქართული: თალიუმი
қазақша: Таллий
Kiswahili: Tali
коми: Таллий
Kreyòl ayisyen: Talyòm
kurdî: Talyûm
Кыргызча: Таллий
кырык мары: Таллий
Latina: Thallium
latviešu: Tallijs
Lëtzebuergesch: Thallium
Ligure: Tallio
Limburgs: Thallium
Livvinkarjala: Tallii
la .lojban.: jinmrtali
lumbaart: Tàlio
magyar: Tallium
македонски: Талиум
മലയാളം: താലിയം
मराठी: थालियम
Bahasa Melayu: Talium
Mìng-dĕ̤ng-ngṳ̄: Thallium
монгол: Талли
မြန်မာဘာသာ: သယ်လီယမ်
Nederlands: Thallium
नेपाली: थ्यालियम
नेपाल भाषा: थ्यालियम
日本語: タリウム
Nordfriisk: Tallium
norsk: Thallium
norsk nynorsk: Thallium
occitan: Talli
ଓଡ଼ିଆ: ଥାଲିଅମ
oʻzbekcha/ўзбекча: Talliy
ਪੰਜਾਬੀ: ਥੈਲੀਅਮ
پنجابی: تھیلیم
Piemontèis: Talio
Plattdüütsch: Thallium
polski: Tal
português: Tálio
română: Taliu
Runa Simi: Thalyu
русский: Таллий
संस्कृतम्: थ्यालियम
Scots: Thallium
Seeltersk: Thallium
shqip: Taliumi
sicilianu: Tàlliu
slovenčina: Tálium
slovenščina: Talij
کوردی: تالیۆم
српски / srpski: Талијум
srpskohrvatski / српскохрватски: Talijum
suomi: Tallium
svenska: Tallium
Tagalog: Talyo
தமிழ்: தாலியம்
татарча/tatarça: Таллий
తెలుగు: థాలియం
Türkçe: Talyum
українська: Талій
اردو: تھیلیئم
vepsän kel’: Tallii
Tiếng Việt: Tali
文言:
Winaray: Talyo
吴语:
ייִדיש: טאליום
Yorùbá: Thallium
粵語:
中文: