Editing Acetal (section)

===Formaldehyde and acetaldehyde===
Formaldehyde forms a rich collection of acetals.  This tendency reflects the fact that low molecular weight aldehydes are prone to self-condensation such that the C=O bond is replaced by an acetal. The acetal formed from [[formaldehyde]] (two hydrogens attached to the central carbon) is sometimes called a ''formal''<ref>Morrison, Robert T. and Boyd, Robert N., "Organic Chemistry (6th ed)". p683. Prentice-Hall Inc (1992).</ref> or the [[methylenedioxy]] group. The acetal formed from [[acetone]] is sometimes called an [[acetonide]].  Formaldehyde forms [[Paraldehyde]] and [[1,3,5-Trioxane]]. [[Polyoxymethylene]] (POM) plastic, also known as "acetal" or "polyacetal", is a polyacetal (and a polyether), and a polymer of [[formaldehyde]]. [[Acetaldehyde]] converts to [[Metaldehyde]].