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How are the axes arranged in the tetragonal crystal system?

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A rough, translucent yellow crystal of elemental sulfur displayed against a solid black background. — crystal A crystal form of elemental sulfur. Sulfur has an atomic weight of about 32.06 atomic mass units (amu), which means that its molar mass is 32.06 grams.

In the tetragonal crystal system, the axes are arranged in a configuration of three mutually perpendicular axes.123

Regarding their lengths, two of these axes (the lateral axes, often designated as $a_{1}$ and $a_{2}$ ) are equal in length, while the third axis (the vertical axis, designated as $c$ ) is of a different length, being either longer or shorter than the other two. This system is further distinguished by an axis of fourfold symmetry, where a 90° rotation of the unit cell brings the atoms into coincidence with their initial positions.123