Calcium chloride (CaCl2) is an ionic compound, meaning that it is composed of positively charged ions (cations) and negatively charged ions (anions). In CaCl2, the calcium atom loses two electrons to become a positively charged calcium ion (Ca2+), while each chlorine atom gains one electron to become a negatively charged chloride ion (Cl-). The electrostatic attraction between the calcium and chloride ions holds the compound together.