Consider the example of water (H 2 O), which has the C 2v symmetry described above. The 2 p x orbital of oxygen has B 1 symmetry as in the fourth row of the character table above, with x in the sixth column). It is oriented perpendicular to the plane of the molecule and switches sign with a C 2 and a σ v '(yz) operation, but remains unchanged with the other two operations (obviously, the character for the identity operation is always +1). This orbital's character set is thus {1, −1, 1, −1}, corresponding to the B 1 irreducible representation. Likewise, the 2 p z orbital is seen to have the symmetry of the A 1 irreducible representation (i.e.: none of the symmetry operations change it), 2 p y B 2, and the 3 d xy orbital A 2. These assignments and others are noted in the rightmost two columns of the table.