Sucrose is a relatively small molecule with 12 carbon atoms (shown in grey), 11 oxygen atoms (red) and 22 hydrogen atoms (white). In the ball and stick model shown here, atoms are represented as small spheres, with the covalent bonds connecting them shown as sticks.
The molecule can be rotated by dragging with the left mouse button. The mouse wheel can be used to zoom in and out, which can also be done by holding the Shift key while dragging with the left mouse button.
The positions of the numerous hydrogen atoms can in principle be deduced from the positions of the other, "heavy" atoms. To make the model a little more tractable, people often choose not to display the hydrogen atoms explicitly:
Sucrose is formed by connecting two ring-shaped molecules, one with a five-atom ring (fructose) and the other with a six-atom ring (glucose). All the connections are single covalent bonds, which can in principle rotate freely. Nonetheless, the rings limit the mobility of the system to a small number of typical conformations, one of which is shown here.
The most significant degree of freedom is in the two bonds for the glycosidic linkage between the two rings (), which allows the two rings to move with respect to each other. The structural variants of the molecules that are formed by these rotations are called conformations ().
The exact size of the molecule varies slightly depending ln the conformation, but the diameter of a sucrose molecule is on the order of 1 nanometer (1 nm = 10-9 meter). We have therefore in many respects entered the domain of nanotechnology.