The Molecular formula of Calcium arsenate (7778-44-1): Ca₃As₂O₈
The Molar mass of Calcium arsenate (7778-44-1): 398.072 g/mol
The Molecular Structure:
Appearance white powder
Density: 3.620 g/cm³, solid
Melting point: 1455°C (decomposes)
Solubility in water: 0.013 g/100 mL (25°C)
Solubility in Organic solvents: insoluble
Solubility in acids: soluble
Other names: Calcium orthoarsenate;Cucumber dust.
Calcium arsenate (7778-44-1) is an extremely poisonous chemical compound. It is highly soluble in water.

Calcium arsenate (7778-44-1) is used extensively as an insecticide and as a fungicide.

Calcium arsenate (7778-44-1) is produced by the reaction of calcium chloride, calcium hydroxide, and sodium arsenate or lime and arsenic acid:
 2CaCl₂ + Ca(OH)₂ + 2Na₂HAsO₄ → Ca₃(AsO₄)₂ + 4NaCl + 2H₂O

Calcium arsenate (7778-44-1) is more toxic than lead arsenate.

NTP 10th Report on Carcinogens, 2000:known to be human carcinogen

Confirmed human carcinogen. When heated to decomposition it emits toxic vapors of NO_x.
Risk Statements: 23/25-45-50/53
23/25:  Toxic by inhalation and if swallowed 
45:  May cause cancer 
50/53:  Very Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment
Safety Statements: 45-53
45:  In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) 
53:  Avoid exposure - obtain special instruction before use 
RIDADR: 1573
HazardClass: 6.1