Methanediol

Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula CH2(OH)2.   It is the simplest geminal diol, and formally the second simplest carbohydrate (after formaldehyde). 

Methanediol is a product of the hydration of formaldehyde H2C=O, and predominates in water solution: the equilibrium constant being about 103, and in a 5% by weight solution of formaldehyde in water, 80% is in the methanediol form.   The dianion, methane-1,1-diolate, is believed to be an intermediate in the crossed Cannizzaro reaction. 

The compound is of some relevance to astrochemistry. 

Safety
Methanediol, rather than formaldehyde, is listed as one of the main ingredients of "Brazilian blowout", a hair-straightening formula marketed in the US.  The equilibrium with formaldehyde has caused concern since formaldehyde in hair straighteners is a health hazard,

See also
 Orthoformic acid (methanetriol)
 Orthocarbonic acid (methanetetrol)

References

Category:Hydrates
Category:Carbohydrates
Category:Geminal diols