subscript/superscript character challenges in HTML

(this entry is a bit of a mess, just posting it for reference now, might get around to expand the topic at a later time)

According to the internet, IE has issues with the UTF-8 version of subscript 2: CO₂ … which unfortunately turns out to be correct, also in IE8. IE just displays an outlined square.

when writing m², you can either use the entity ² or <sup>2</sup>. There is no entity for subscript-2 and the UTF-character ₂ doesn’t work in IE Without some extra CSS in the document they differ a bit, ² being more typographically correct. <sup> and <sub> elements messes up the line spacing.

Examples (entities vs. sup/sub): m² vs. m² and CO₂ vs. CO₂

_{Related info:}

• Math unicode entities
• Browser test page for unicode character SUBSCRIPT TWO