(CH3COO)2Mg · 4H2O
M.W.: 214.45
Physical State : Solid
Appearance : White powder
Odor : Odorless
Color : White
Assay : ≥99.0%
Density :  1.454 g/cm3
Solubility : 1 M in H2O at 20 °C, clear, colorless
It is also highly soluble in water or alcohol.

Magnesium acetate is used in chemistry and molecular biology as a reagent and a source of magnesium. Magnesium has a variety of biological roles in enzymology, cell membrane and wall structural integrity, muscle cell physiology, and nucleic acid structure. 
Magnesium is an essential co-factor in many enzymes, including deoxyribonuclease (DNase), the restriction enzymes EcoR I and EcoR V, and Ribonuclease H. Magnesium also stabilizes polymeric nucleic acids such as transfer RNA and ribozymes.
Magnesium acetate has been widely used in the crystallization of proteins.