Diose

{{Short description|Monosaccharide with only two carbon atoms}}

File:Glycolaldehyde.svg

A diose is a monosaccharide containing two carbon atoms. Because the general chemical formula of an unmodified monosaccharide is (C·H₂O)_n, where n is three or greater, it does not meet the formal definition of a monosaccharide.{{Cite book|title=Biochemistry|last=Mathews|first=Christopher K.|last2=Van Holde|first2=Kensal Edward|last3=Ahern|first3=Kevin G.|date=2000|publisher=Benjamin Cummings|isbn=0805330666|edition=3rd|location=San Francisco, Calif.|pages=280|oclc=42290721}} However, since it does fit the formula (C·H₂O)_n, it is sometimes thought of as the most basic sugar.{{cite book |title=Text Book of Physiological Chemistry in Thirty Lectures|last=Abderhalden|first=Emil|author-link=Emil Abderhalden|translator=William T. Hall|translator2=George Defren|year=1908|orig-year=1906|publisher=J Wiley & Sons|location=New York|url=https://archive.org/details/textbookofphysio00abde|page=[https://archive.org/details/textbookofphysio00abde/page/19 19]|access-date=23 April 2014}}

There is only one possible diose, glycolaldehyde (2-hydroxyethanal), which is an aldodiose (a ketodiose is not possible since there are only two carbons).