Carbonic Acid is a weak, inorganic acid with the molecular formula H2CO3. It is formed when carbon dioxide is dissolved in water, and only exists as a solution. It is found in sodas, champagne and other "bubbly" drinks. It is found to be corrosive to limerock and calcium, causing the formation of many caves.
Above is a three-dimensional model of a Carbonic Acid molecule. The central atom (gray) is carbon. One oxygen (red) is double-bonded to the carbon, and two other oxygens are single-bonded to it. To each of the oxygens which are single-bonded to the carbon, a hydrogen (white) is also single-bonded.
Carbonic Acid is a AX3 molecule. This means that there are three atoms directly attatched to the central atom, and there are no lone electron pairs on the central atom. AX3 molecules such as carbonic acid take the shape called Triangular planar. Triangular planar molecules form bonds which separate each of the atoms attached to the central atom by 120 degree angles.