That's not quite right. While carbon dioxide and water are involved in the process, calcium bicarbonate (Ca(HCO3)2) forms when carbon dioxide reacts with water in the presence of calcium carbonate (CaCO3).

Here's a breakdown of the reaction:

1. Carbon dioxide dissolves in water: CO2 + H2O ⇌ H2CO3 (carbonic acid)

2. Carbonic acid reacts with calcium carbonate: H2CO3 + CaCO3 ⇌ Ca(HCO3)2

Essentially, the reaction involves the following:

* Carbon dioxide: The source of the carbonate ions (CO3²⁻)

* Water: Provides the necessary environment for the reaction to occur.

* Calcium carbonate: The source of the calcium ions (Ca²⁺).

This process is important in the formation of hard water and in the dissolution of limestone caves.

So, while carbon dioxide and water are involved, they don't form calcium bicarbonate directly. The presence of calcium carbonate is crucial.