Copper(II) arsenate

Copper(II) arsenate
IUPAC name Copper(II) arsenate
Other names Copper arsenate
Identifiers
CAS number	7778-41-8 Y
PubChem	26065
ChemSpider	24279 Y
Jmol-3D images	Image 1
SMILES [Cu+2].[Cu+2].[Cu+2].[O-][As]([O-])(=O)[O-].[O-][As]([O-])([O-])=O
InChI InChI=1S/2AsH3O4.3Cu/c2*2-1(3,4)5;;;/h2*(H3,2,3,4,5);;;/q;;3*+2/p-6 Y Key: RKYSWCFUYJGIQA-UHFFFAOYSA-H Y InChI=1/2AsH3O4.3Cu/c2*2-1(3,4)5;;;/h2*(H3,2,3,4,5);;;/q;;3*+2/p-6 Key: RKYSWCFUYJGIQA-CYFPFDDLAM
Properties
Molecular formula	Cu3(AsO4)2
Molar mass	468.48 g/mol
Appearance	blue or bluish green powder
Density	5.2 g/cm3
Melting point	1100 °C
Solubility in water	insoluble
Solubility	soluble in ammonia, dilute acids
Hazards
EU Index	Not listed
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Copper arsenate (Cu₃(AsO₄)₂.4H₂O, or Cu₅H₂(AsO₄)₄.2H₂O), also called copper orthoarsenate or tricopper arsenate or tricopper orthoarsenate, is a blue or bluish-green powder insoluble in water and alcohol and soluble in aqueous ammonium and dilute acids. Its CAS number is [7778-41-8] or [10103-61-4].

Uses

Copper arsenate is an insecticide used in agriculture. It is also used as a herbicide, fungicide, and a rodenticide. It is also used as a poison in slug baits.

Copper arsenate can also be a misnomer for copper arsenite, especially when meant as a pigment.

Natural occurrences

Anhydrous copper arsenate, Cu₃(AsO₄)₂, is found in nature as the mineral lammerite.^[1] Copper arsenate tetrahydrate, Cu₃(AsO₄)₂.4H₂O, occurs naturally as the mineral rollandite.^[2]

Related compounds

Copper arsenate hydroxide or basic copper arsenate (Cu(OH)AsO₄) is a basic variant with CAS number [16102-92-4]. It is found naturally as the mineral olivenite. It is used as an insecticide, fungicide, and miticide. Its use is banned in Thailand since 2001.[1]

See also

• Lead arsenate
• Calcium arsenate
• Paris Green (copper arsenate-acetate)
• Chromated copper arsenate
• Scheele's Green (copper arsenite)

External links

• National Pollutant Inventory - Copper and compounds fact sheet

References

1. ^ Hawthorne, F. C. (1986). "Lammerite, Cu₃(AsO₄)₂, a modulated close-packed structure". American Mineralogist 71: 206–209. http://www.minsocam.org/ammin/AM71/AM71_206.pdf. 
2. ^ Sarp, H.; Černý, R. (2000). "Rollandite, Cu₃(AsO₄)₂·4H₂O, a new mineral". Eur. J. Mineral. 12: 1045–1050. doi:10.1127/0935-1221/2000/0012-1045.