Chloride Family

• Magnesium chloride is a Period 3 chloride, meaning it is made up of an element found on the third period, or row, of the periodic table, and chlorine. Common period 3 chlorides include sodium chloride (NaCl), magnesium chloride (MgCl2), aluminum chloride (AlCl3), and sulphur chloride (S2Cl2). All the period 3 elements form chlorides, except for argon and chlorine itself.
  
  

Crystal Lattice Structure

• According to the UK A-Level Chemistry Guide, magnesium chloride consists of a large ionic lattice at room temperature. This means that it consists of layers of ions that are attached to one another via ionic bonds. Ionic bonds are bonds formed when one element gives an electron to another element. If you had one molecule of magnesium chloride, it would consist of one atom of magnesium and two atoms of chlorine. The two atoms of chlorine each give an electron to the atom of magnesium, forming an ionic bond.
  
  

Magnesium Chloride's High Melting and Boiling Points

• The lattice structure strengthens the ionic bonds between magnesium and chlorine. In order to break those bonds, you must apply a large amount of heat. When sufficient heat is applied, magnesium chloride melts into a liquid. Still more heat is needed to boil the liquid.
  
  

Magnesium Chloride and Electrical Conductivity

• According to the UK A-Level Chemistry Guide, solid magnesium chloride does not conduct electricity. However, when magnesium chloride melts, the magnesium and chlorine atoms separate from each other, becoming charged ions. Liquid magnesium chloride conducts electricity well.
  
  

Hydrolysis and Acidity

• Magnesium chloride readily dissolves in water. This process is called hydrolysis. Unlike table salt, which gives a neutral solution upon dissolving in water, magnesium chloride gives a slightly acidic solution. The UK A-Level Chemistry Guide says that water mixed with magnesium chloride has a pH of 6.