STRONTIUM - Sr
Properties of Strontium:
Alkaline earth metal. Light yellow, malleable. In the air is covered with oxide-nitride film. Colors the flame of a gas burner in a bright red color. High reactivity. Reacts with oxygen, nitrogen, hydrogen, halogen with heating. Strong reducing agent, oxidised by water, diluted acids, ammonia.
Molar mass | g/mol | 87.62 |
Density | g/cm3 | 2.63 |
Melting point | °C | 768 |
Boiling point | °C | 1390 |
Methods for the preparation of Strontium:
4SrO+ 2Al = 3Sr + (SrAl2)O4 (1200°C).
3SrCl2 + 2Al = 3Sr + 2AlCl3 (600-700°C).
SrCl2(liquid)→ Electrolysis → Sr(on cathode) + Cl2↑(on anode).
Сhemical reactions with metal Strontium:
Sr + 2H2O = Sr(OH)2↓ + H2↑ (normail temp.),
2Sr + H2O(vapor) = SrO + SrH2 (200-300°C).
Sr + 2HCl(diluted) = SrCl2 + H2.
4Sr + 10HNO3(diluted) = 4Sr(NO3)2 +N2O↑ + 5H2O,
4Sr + 10HNO3(highly diluted) = 4Sr(NO3)2 + NH4NO3 + 3H2O.
Sr + H2 = SrH2 (200-500°C).
Sr + O2 = 2SrO (over 250°C, burning on air).
Sr + Cl2 = SrCl2 (200-400°C).
3Sr + N2 = Sr3N2 (450-500°C, burning on air).
Sr + 2C(graphite) = SrC2 (500°C).
6Sr + 2NH3(gas) = Sr3N2 + 3SrH2 (600-650°C).
Sr + 6NH3(liquid) = [Sr(MH3)6](blue) [-40°C, in the atm. of Ar],
Sr + 2NH3(liquid) = Sr(NH2)2↓ + H2 (catalyst Pt).
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