Elements and compounds of gallium, indium and thallium

1.
The simple substance of gallium, indium and thallium

The metallic properties of aluminum, indium, and thallium are successively enhanced
.

Gallium and indium are silver white and silver gray

Like aluminum, it is an amphoteric metal, while indium and thallium are alkaline metals
.

Gallium, indium, and thallium can react with non-oxidizing acids as well as oxidizing acids

2.

Compounds of gallium, indium and thallium

The stability of oxides of +trivalent gallium, indium, and thallium decreases sequentially
.

For example, T ₁₂ O ₃ is not very stable and easily decomposes when heated

T _l2 O ₃ =Tl ₂ O+O ₂

The stability of the hydroxides of gallium, indium, and thallium also decreases sequentially, and the hydroxide of +3 thallium, Tl(OH) ₃ does not even exist
.

But the hydroxide TIOH of +1 valence wheel is very stable

Ga ₂ O ₃ and Ga(OH) ₃ are both amphoteric compounds
.

The anomaly is that Ga(OH) ₃ is more acidic than Al(OH) ₃

In ₂ O ₃ , In(OH) ₃ , Tl ₂ O ₃ , and TIOH are all alkaline
.

Among them, TIOH is a strong base, similar to KOH

Tl ³⁺ with strong oxidizing (Tl ³⁺ / TI ⁺ standard electrode potential of 1.

25V), capable of many typical reducing agents (e.
g.

Among the halides of +3 thallium, TICI _{3 is} easily decomposed by heat, while TIBr ₃ and TlI ₃ do not exist at room temperature
.

TICI ₃ =TICI+Cl ₂

TI ³⁺ has a strong oxidizing property, which is determined by the valence electron configuration of thallium
.

The valence electron configuration of thallium is 6s ² 6p ¹ , because 6s ² electrons have a strong drill-through effect and are not easy to lose, so TI+ is relatively stable
.
This property of 6s ² electrons that is not easy to lose is called the "inert electron pair effect"
.
The strong oxidation of Tl ³⁺ is also caused by the "inert electron pair effect"
.
Lead and bismuth of the same period also have an inert electron pair effect
.