Formaldehyde
= Formaldehyde
{wiki}
= Methanal
{synonym}
The planar molecule $\mathrm{H_2CO}$. With the C=O bond along $z$ and the molecule in the $xz$ plane, its $C_{2v}$ vibrational representation is $3A_1+2B_1+B_2$. Interchanging the $x$ and $y$ axes interchanges the $B_1$ and $B_2$ labels; physical activity is unchanged.