Copper(I) sulfate

Copper(I) sulfate, also known as cuprous sulfate, is an inorganic compound with the chemical formula Cu₂SO₄. It is a white solid, in contrast to copper(II) sulfate, which is blue in hydrous form. Compared to the commonly available reagent, copper(II) sulfate, copper(I) sulfate is unstable and not readily available.^[1]

Copper(I) sulfate

Names
IUPAC name Copper(I) sulfate
Systematic IUPAC name Copper(I) sulfate
Other names Copper sulfate; Cuprous sulfate; Dicopper sulfate
Identifiers
CAS Number	17599-81-4
3D model (JSmol)	Interactive image
ChemSpider	118749
ECHA InfoCard	100.159.746
PubChem CID	134737
CompTox Dashboard (EPA)	DTXSID30889663
InChI InChI=1S/2Cu.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Key: WIVXEZIMDUGYRW-UHFFFAOYSA-L InChI=1/2Cu.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Key: WIVXEZIMDUGYRW-NUQVWONBAI
SMILES [O-]S(=O)(=O)[O-].[Cu+].[Cu+]
Properties
Chemical formula	Cu2SO4
Molar mass	223.15 g mol−1
Appearance	White
Density	4.12 g cm−3[1]
Melting point	110 °C
Solubility in water	decomposes
Structure[1]
Crystal structure	orthorhombic
Space group	Fddd
Lattice constant	a = 4.748(3) Å, b = 13.96(1) Å, c = 10.86(1) Å
Formula units (Z)	8
Hazards
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 mg/m3 (as Cu)[2]
REL (Recommended)	TWA 1 mg/m3 (as Cu)[2]
IDLH (Immediate danger)	TWA 100 mg/m3 (as Cu)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Structure

Cu₂SO₄ crystallizes in the orthorhombic space group Fddd. Each oxygen in a sulfate anion is bridged to another sulfate by a copper atom, and the Cu−O distances are 196 pm.^[1]

Synthesis

Cuprous sulfate is produced by the reaction of copper metal with sulfuric acid at 200 °C:^[3]

2 Cu + 2 H₂SO₄ → Cu₂SO₄ + SO₂ + 2 H₂O

Cu₂SO₄ can also be synthesized by the action of dimethyl sulfate on cuprous oxide:^[4]

Cu₂O + (CH₃O)₂SO₂ → Cu₂SO₄ + (CH₃)₂O

The material is stable in dry air at room temperature but decomposes rapidly in presence of moisture or upon heating. It decomposes into copper(II) sulfate pentahydrate upon contact with water.^[4]

Cu₂SO₄ + 5 H₂O → Cu + CuSO₄ · 5 H₂O