Magnesium chloride hexahydrate known halogen flake, the formula MgCl2 · 6H2O, molecular weight: 203.3. Colorless crystals. Soluble in water and ethanol, it is easy to deliquesce when the humidity is high. 116~118 °C hot melt decomposition. It is mixed with magnesia and water to form magnesium cement. It reacts with an alkali metal or alkaline earth metal hydroxide. 
Appearance: light yellow or white flake, powdery, irregular granular 
Properties: colorless and deliquescent crystal, highly soluble in water, usually with six molecules of crystal water, namely MgCI2.6H2O, but heated to 95 At °C, the crystal water is lost. When it is above 135 °C, it begins to decompose and releases hydrogen chloride (HCI) odor. The halogen sheet is colorless monoclinic crystal. The industrial product tends to have a yellow-brown magnesium chloride content of about 30%-50% and also contains magnesium sulfate. Impurities such as compounds, have a bitter taste. Soluble in water and ethanol, it is easy to deliquesce at higher temperatures