RUBIDIUM - Rb

Properties Rubidium Rb:

An alkali metal. White, soft, very low melting. The vapor of rubidium is painted in a greenish-blue color. Chemically dissolves in liquid NH3 (dark-blue solution), in the melt RbOH. Extremely reactive, strong reducing agent. Vigorously reacts with oxigen of air, water (there is inflammation of the metal and released hydrogen), dilute acids, non-metals, ammonia, hydrogen sulfide. Does not react with nitrogen. It is well preserved only under a layer of paraffin oil or vaseline. With the mercury forms an amalgam. Colors the flame of a gas burner in a purple color.


Obtaining rubidium Rb:

2RbH = 2Rb + H2 (t > 200° С).

2Rb2O = Rb2O2 + 2 Rb (400-550° С).

RbOH (liquid) → Electrolysis → 4Rb (cathode) + O2↑(anode) + 2 H2O.

2RbCl (liquid) → Electrolysis → 2Rb (cathode) + Cl2↑(anode).

2RbCl + 2 H2O → Electrolysis → H2↑ (cathode) + Cl2↑(anode) + 2 RbOH,

2RbCl(melt)(on Hg-cathode) → Electrolysis → 2Rb (cathode) + Cl2↑ (anode).


Сhemical reactions with rubidium Rb:

2Rb + 2H2O = 2 RbOH + H2↑.

2Rb + 2HCl (diluted) = 2RbCl + H2↑.

8Rb + 6H2SO4 (diluted, cold) = 4 Rb2SO4 + SO2 + S↓ + 6 H2O (impurity H2S).

21Rb + 26HNO3 (diluted, cold) = 21 RbNO3 + NO↑ + N2O↑ + N2↑ + 13 H2O.

2Rb + 2RbOH = 2 Rb2O + H2 (400° С).

2Rb + H2 = 2 RbH (300-350° С, pressure).

Rb + O2 (air) = RbO2 (burning).

4Rb + O2 = 2Rb2O (in the cold),

Rb → + O2 → Rb2O2 → + O2 → time → RbO2↓(-50° С, in the liquid NH3).

4Rb + O2 + 2 H2O = 4 RbOH (normal temp.).

2Rb + E2 = 2RbE (normal temp.; E = F, Cl, Br, I).

2Rb + S = Rb2S (100-130° С).

2Rb + 2 H2S (saturated) = 2 RbHS ↓ + H2↑ (in benzene).

2Rb + 2 NH3 (gas) = 2 RbNH2 + H2 (40-60° С).

Rb + 6 NH3 (liquid) = [Rb(NH3)6]      (-40° С),

[Rb(NH3)6] + nNH3 (liquid) ↔ [Rb(NH3)6]+ + e-·nNH3.

4Rb + 3SiO2 = Rb2SiO3 + Si (t > 300° C).


 

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