C5H10O5

C5H10O5 is the molecular formula shared by a family of pentose sugars. The most well-known members are the aldopentoses, including D-ribose, D-arabinose, D-xylose, and D-lyxose. These sugars consist of five carbon atoms, ten hydrogens, and five oxygens, and they can exist in both open-chain and cyclic forms.

In their open-chain form, aldopentoses contain an aldehyde group at carbon 1 and multiple hydroxyl groups on the remaining carbons. In aqueous solution, they readily cyclize to form five-membered rings called furanoses; ribose, for example, commonly adopts ribofuranose forms, which can exist as alpha or beta anomers depending on the orientation of the anomeric hydroxyl.

Biological and chemical significance centers on ribose in particular: D-ribose is a key component of RNA, forming the sugar backbone of ribonucleotides. Ribose-5-phosphate is an important intermediate produced via the pentose phosphate pathway, linking nucleotide biosynthesis with cellular metabolism. A related sugar, deoxyribose, has formula C5H10O4 and forms the backbone of DNA.

Properties of C5H10O5 sugars include high water solubility and polar character due to multiple hydroxyl groups; they are classified as reducing sugars because their aldehyde group can be oxidized. The open-chain form has four chiral centers, yielding 16 possible stereoisomers; natural nutrition and biology predominantly feature the D-configuration.