The anhydrous chloride is formed by heating strontium or its monoxide in chlorine, or by heating the hydrated chloride in a current of hydrochloric acid gas.
Several hydrated forms are known, yielding salts known as columbates.
A hydrated form is prepared when a solution of titanic acid in hydrochloric acid is digested with copper, or when the trichloride is precipitated with alkalis.
The amorphous form readily slakes with water, and the aqueous solution yields a crystalline hydrated hydroxide approximating in composition to Sr(OH) 2.8H 2 O or Sr(OH) 2.9H 2 O, which on standing in vacuo loses some of its water of crystallization, leaving the monohydrated hydroxide, Sr(OH) 2 H 2 O.
A hydrated dioxide, approximating in composition to SrO 2.8H 2 O, is formed as a crystalline precipitate when hydrogen peroxide is added to an aqueous solution of strontium hydroxide.