iron(II) sulfate, when dissolved in water
Names
IUPAC nameIron(II) sulfate
Other names
Ferrous sulfate, Green vitriol, Iron vitriol, Copperas, Melanterite, Szomolnokite
Identifiers
CAS Number: 7720-78-7
JSmol: Interactive image
ChEBI: CHEBI:75832
ChEMBL: ChEMBL1200830
ChemSpider: 22804
ECHA InfoCard: 100.028.867
EC Number: 231-753-5
PubChem: 24393
RTECS number: NO8500000 (anhydrous)
NO8510000 (heptahydrate)
UNII: 2IDP3X9OUD
UN number: 3077
Properties
Chemical formula: FeSO
Molar mass: 151.91 g/mol (anhydrous)
169.93 g/mol (monohydrate)
241.99 g/mol (pentahydrate)
260.00 g/mol (hexahydrate)
278.02 g/mol (heptahydrate)
Appearance: White crystals (anhydrous)
White-yellow crystals (monohydrate)
Blue-green crystals (heptahydrate)
Odor: Odorless
Density: 3.65 g/cm (anhydrous)
3 g/cm (monohydrate)
2.15 g/cm (pentahydrate)
1.934 g/cm (hexahydrate)
1.895 g/cm (heptahydrate)33333
Melting point: 680 °C (1,256 °F; 953 K)
(anhydrous) decomposes
300 °C (572 °F; 573 K)
(monohydrate) decomposes
60–64 °C (140–147 °F; 333–337 K)
(heptahydrate) decomposes
Solubility in water: Monohydrate:
44.69 g/100 mL (77 °C)
35.97 g/100 mL (90.1 °C)
Heptahydrate:
15.65 g/100 mL (0 °C)
20.5 g/100 mL (10 °C)
29.51 g/100 mL (25 °C)
39.89 g/100 mL (40.1 °C)
51.35 g/100 mL (54 °C)
Solubility: alcohol
Solubility: 6.4 g/100 g (20 °C)
Vapor pressure: 1.95 kPa (heptahydrate)
Magnetic susceptibility:(anhydrous)
(monohydrate)
(heptahydrate)
1.2410 cm/mol1.0510 cm/mol1.1210 cm/mol+1010 cm/mol
Refractive index: 1.591 (monohydrate)
1.526–1.528 (21 °C, tetrahydrate)
1.513–1.515 (pentahydrate)
1.468 (hexahydrate)
1.471 (heptahydrate)
Structure
Crystal structure: Orthorhombic
Space group: Pnma, No. 62 (anhydrous)
C2/c, No. 15 (monohydrate, hexahydrate)
P2/n, No. 14 (tetrahydrate)
P, No. 2 (pentahydrate)
P2/c, No. 14 (heptahydrate)111
Point group: 2/m 2/m 2/m (anhydrous)
2/m (monohydrate, tetrahydrate, hexahydrate, heptahydrate)
(pentahydrate)1
Lattice constant: = 8.704(2) Å, = 6.801(3) Å, = 4.786(8) Å (293 K, anhydrous)
Coordination geometry: Octahedral (Fe)
Thermochemistry
Specific
heat capacity: 100.6 J/mol·K (anhydrous)
394.5 J/mol·K (heptahydrate)
Std molar
entropy: 107.5 J/mol·K (anhydrous)
409.1 J/mol·K (heptahydrate)
Std enthalpy of
formation: −928.4 kJ/mol (anhydrous)
−3016 kJ/mol (heptahydrate)
Gibbs free energy: −820.8 kJ/mol (anhydrous)
−2512 kJ/mol (heptahydrate)
Pharmacology
ATC code: WHOB03AA07
Hazards
GHS pictograms:
GHS signal word: Warning
GHS hazard statements: H302 H315 H319
GHS precautionary statements: P305+351+338
NFPA 704:
LD
median dose: 237 mg/kg (rat, oral)
NIOSH
REL: TWA 1 mg/m3
Related compounds
cations: Cobalt(II) sulfate
Related compounds: Iron(III) sulfate
Except where otherwise noted, data are given for materials in their(at 25 °C [77 °F], 100 kPa).Except where otherwise noted, data are given for materials in their(at 25 °C [77 °F], 100 kPa).
Infobox references