CESIUM - Cs
Properties of metallic cesium Cs:
An alkali metal. White (on the cut - light yellow), soft, very low melting. The vapor of cesium is painted in a greenish-blue color. Chemically dissolves in liquid ammonia (dark blue solution), the melt of CsOH. It is extremely reactive, the strongest reducing agent, reacts with oxygen in the air, water (there is inflammation of the metal and hydrogen is released), 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 the blue.
Obtaining metallic cesium Cs:
2 Cs2O = Cs2O2 + 2 Cs (300—500° C).
4 CsOH (liquid) → Electrolysis 4 Cs (cathode) + O2↑ (anode) + 2 H2O.
2 CsCl + 2H2O → Electrolysis H2↑ (cathode) + Cl2↑ (anode) + 2 CsOH,
2 CsCl (melt) (on Hg-cathode)→ Electrolysis 2 Cs (cathode) + Cl2↑(anode).
Сhemical reactions with metallic cesium Cs:
2 Cs + 2 H2O = 2CsOH + H2↑.
2 Cs + 2 HCl (diluted) = 2 CsCl + H2↑.
8 Cs + 6 H2SO4 (diluted, cold) = 4 Cs2SO4 + SO2 + S↓ + 6H2O (impurity H2S),
21 Cs + 26 HNO3 (diluted, cold) = 21 CsNO3 + NO↑ + N2O↑ + N2↑ + 13H2O.
2 Cs + 2 CsOH = 2 Cs2O + H2↑ (300—350° C).
2 Cs + H2 = 2 CsH (300—350° C, pressure).
Cs + O2(air) = CsO2 (combustion),
4 Cs + O2 = 2 Cs2O (in the cold), Cs →(O2) Cs2O2↓ →(O2), (time) CsO2↓ (-50° C, in the liquid NH3).
4 Cs + O2 + 2 H2O = 4 CsOH.
2 Cs + E2 = 2 CsE (normal temp.; E = F, Cl, Br, I).
2 Cs + S = Cs2S (100—130° C).
2 Cs + 2 H2S (saturated) = 2 CsHS ↓ + H2 ↑ (in benzene).
2 Cs + 2 NH3 (gas) = 2 CsNH2 + H2 (30—45° C).
Cs + 6 NH3 (liquid) = [Cs(NH3)6](time, blue) [-40° C],
[Cs(NH3)6] + nNH3 (liquid) ↔ [Cs(NH3)6]+ + e-·nNH3.
4 Cs + 3 SiO2 = 2 Cs2SiO3 + Si (t>300° C).
