Iron(II) nitrate

From Crystal growing


   Iron(II) nitrate   
Names: iron(II) nitrate

Formula: Fe(NO3)2 (anhydrous)
Fe(NO3)2 · 6H2O (hexahydrate)
Fe(NO3)2 · 9H2O (nonahydrate)
SMILES: [N+](=O)([O-])[O-].[N+](=O)([O-])[O-].[Fe+2]
Molar mass: 179.853 g/mol (anhydrous)
287.942 g/mol (hexahydrate)
341.987 g/mol (nonahydrate)
Crystal system: orthorhombic (hexahydrate)
α=90°, β=90°, γ=90°
Shapes:
https://en.crystalls.info/w/uploads/media/f/f6/Prolongated_hexagonal_flat_prism.json
https://en.crystalls.info/w/uploads/media/1/12/Trapezoidal_flat_prism.json

Color: pale green
Melting point: 60.5 °C333.65 K <br />140.9 °F <br />600.57 °R <br /> (hexahydrate)
Magnetic properties: paramagnetic
Stability: stable (hexahydrate)
hygroscopic (anhydrous)
Hardness: fragile
Toxicity: slightly toxic

Description

Inorganic compound, salt of bivalent transitional metal iron and inorganic nitric acid. From water solutions crystallizes as hexahydrate and nonahydrate.

Precursors

Reaction between iron(II) oxide, sulfide, hydroxide or hydroxycarbonate and nitric acid

Chemical equation:

FeO + 2HNO3 = Fe(NO3)2 + H2O
FeS + 2HNO3 = Fe(NO3)2 + H2S↑
Fe(OH)2 + 2HNO3 = Fe(NO3)2 + 2H2O
Fe2CO3(OH)2 + 4HNO3 = 2Fe(NO3)2 + CO2↑ + 3H2O


For preparation of 100.00g of iron(II) nitrate hexahydrate а 24.95g of iron(II) oxide or 30.53g of sulfide or 31.21g of hydroxide or 35.72g of hydroxycarbonate and 67.33g of 65% acid is required.

Add acid to the flask, then add small parts of iron compound with stirring until it will totally dissolve or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.

Reaction between metal iron and diluted nitric acid

Chemical equation:

4Fe + 10HNO3 = 4Fe(NO3)2 + NH4NO2 + 3H2O


For preparation of 100.00g of iron(II) nitrate hexahydrate а 19.39g of pure iron and 84.17g of 65% acid is required.

Add cold diluted acid solution to the flask, then add iron pieces, shavings or powder and stir it until gas emission will stop.

Reaction between iron(II) sulfate and calcium or lead(II) nitrate

You can use iron chloride instead of sulfate if you use lead salt.
Chemical equation:

FeSO4 + Ca(NO3)2 = CaSO4↓ + Fe(NO3)2
FeSO4 + Pb(NO3)2 = PbSO4↓ + Fe(NO3)2
FeCl2 + Pb(NO3)2 = PbCl2↓ + Fe(NO3)2


For preparation of 100.00g of iron(II) nitrate hexahydrate а 96.55g of iron(II) sulfate heptahydrate or 69.05g of iron(II) chloride tetrahydrate and 115.03g of lead(II) nitrate or 82.01g of calcium nitrate tetrahydrate is required.

Add to the flask with calcium or lead nitrate solution small parts of iron salt solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and discard, then filter the solution carefully.

Reaction between iron(II) hydroxide or hydroxycarbonate and ammonium nitrate

Chemical equation:

Fe(OH)2 + 2NH4NO3 = Fe(NO3)2 + 2H2O + 2NH3
Fe2CO3(OH)2 + 4NH4NO3 = 2Fe(NO3)2 + 3H2O + 2NH3↑ + CO2


For preparation of 100.00g of iron(II) nitrate hexahydrate а 31.21g of iron(II) hydroxide or 35.72g of hydroxycarbonate and 55.60g of ammonium nitrate is required.

Add to the flask suspended in water iron compound and then add small parts of hot ammonium nitrate solution with heating and stirring. Emission of large amount of ammonia will begin.Attention, exuding ammonia irritates eyes and lungs! The synthesis should be carried out only in a fume hood or outdoors!

Notes

The solution absorbs moisture from the air, so growth is hard enough.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

Temperatureгр/100,00 гр water
(anhydrous)(hexahydrate)
0°C273.15 K <br />32 °F <br />491.67 °R <br />71.03113
10°C283.15 K <br />50 °F <br />509.67 °R <br />~76.8134
15°C288.15 K <br />59 °F <br />518.67 °R <br />~79.6
20°C293.15 K <br />68 °F <br />527.67 °R <br />82.48
25°C298.15 K <br />77 °F <br />536.67 °R <br />86.92
30°C303.15 K <br />86 °F <br />545.67 °R <br />~98.3
40°C313.15 K <br />104 °F <br />563.67 °R <br />~121
50°C323.15 K <br />122 °F <br />581.67 °R <br />~144
60°C333.15 K <br />140 °F <br />599.67 °R <br />166.67


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