Unicode Subscripts and Superscripts - Uses

Uses

Most fonts that include these characters design them for mathematical numerator and denominator glyphs, which are smaller than normal characters but are aligned with the cap line and the baseline, respectively. When used with the solidus, these glyphs are useful for making arbitrary diagonal fractions (similar to the ½ glyph).

This was not the intended use of these characters when Unicode was designed. The intended use was to allow chemical and algebra formulas to be written without markup. Proper appearance of these requires true superscript and subscript, H₂O probably looks better using a subscript markup than using these characters (H₂O)

Another Unicode character, the fraction slash U+2044 is visually similar to the solidus, but when used with the ordinary digits (not the superscripts and subscripts) was intended to tell a layout system that a fraction, such as ¹¹⁄₁₂, is preferred. Most font layout systems do not actually produce this.