What is ab2?

Ab2, or AB2, typically refers to a molecular geometry in chemistry where a central atom (A) is bonded to two other atoms (B) with no lone pairs on the central atom. This results in a linear arrangement of the atoms, with a bond angle of 180 degrees. A common example of an AB2 molecule is carbon dioxide (CO2). The designation helps in understanding the shape and bonding properties of molecules in the context of VSEPR theory.