Lammerite

Copper(II) arsenate

Names
IUPAC name Copper(II) arsenate
Other names Copper arsenate
Identifiers
CAS Number	7778-41-8 Y
3D model (Jmol)	Interactive image
ChemSpider	24279 Y
PubChem	26065
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
SMILES [Cu+2].[Cu+2].[Cu+2].[O-][As]([O-])(=O)[O-].[O-][As]([O-])([O-])=O
Properties
Chemical formula	Cu3(AsO4)2
Molar mass	468.48 g/mol
Appearance	blue or bluish green powder
Density	5.2 g/cm3
Melting point	1,100 °C (2,010 °F; 1,370 K)
Solubility in water	insoluble
Solubility	soluble in ammonia, dilute acids
Hazards
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 1 mg/m3 (as Cu)
REL (Recommended)	TWA 1 mg/m3 (as Cu)
IDLH (Immediate danger)	TWA 100 mg/m3 (as Cu)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Copper arsenate (Cu₃(AsO₄)₂.4H₂O, or Cu₅H₂(AsO₄)₄.2H₂O), also called copper orthoarsenate, tricopper arsenate, cupric 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.

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.

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

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.