Characteristic Reactions of Calcium Ions (Ca²⁺)


• Most common oxidation state: +2
• M.P. 845º
• B.P. 1420º
• Density 1.55 g/cm3
• Characteristics: Calcium is a rather soft, very active metal. Very similar to barium in its chemical properties.

Characteristic reactions of Ca²⁺

Sulfate Ion

Soluble sulfates, such as sulfuric acid, do not precipitate $$\ce{Ca^{2+}}$$ as calcium sulfate, unless the calcium ion is present in very high concentrations.

Sodium Hydroxide

Calcium hydroxide can be precipitated by addition of sodium hydroxide if $$\ce{Ca^{2+}}$$ is present in moderate concentration (>~0.02 M).

Ammonium Carbonate

This forms a precipitate similar to that formed with $$\ce{Ba^{2+}}$$.

Sodium Oxalate

The behavior is similar to that of $$\ce{Ba^{2+}}$$, but the precipitate is much less soluble in water and is insoluble in acetic acid. $$\ce{CaC2O4 \cdot H2O}$$ is soluble in mineral acids.

Flame Test

Solutions of calcium salts give a yellow-red color to a Bunsen burner flame, sometimes with a sparkly appearance.

No Reaction

$$\ce{Cl^{-}}$$, $$\ce{NH3(aq)}$$

This page titled Characteristic Reactions of Calcium Ions (Ca²⁺) is shared under a not declared license and was authored, remixed, and/or curated by James P. Birk.