The Cellobiose molecule - rotatable in 3 dimensions

Cellobiose is a disaccharide - formula C₁₂H₂₂O₁₁ - consisting of two glucose units (12 carbon atoms, and 2 ring-shaped structures, each containing an oxygen atom) - like maltose.

However there are major differences between maltose and cellobiose:

Each glucose unit is effectively the opposite way up, a reflection of the arrangement in cellulose. This can be seen when the carbon 6 and associated groups are highlighted.

Additionally, the two sugars are linked via a differently oriented glycosidic bond - a β (beta) 1-4 bond - between opposite ends of the 2 glucose molecules. Label / unlabel bonding carbon atom numbers. This bond - effectively an oxygen bridge - is formed as a result of a condensation reaction.

This apparently linear linkage is the basis for cellulose, which forms microfibrils running parallel to others, stabilised by hydrogen bonds. Show ... hide H bonds between these sections.

Note that as in maltose, one of these ring-shaped sections is in equilibrium with an open-chain form in which Carbon 1 has a CHO aldehyde group which gives it reducing properties, so that it reacts with reagents such as Benedict's.