HOw to use HTML Symbols in Joomla

I'm trying to use the empty HTML symbol, ∅, in the Joomla content editor. The symbol displays properly if I edit the HTML source and add the code开发者_如何学C, ∅, to the HTML editor. But when I save an article, then ∅ converts to ? character and I'm not sure why it is happening.

Convert your database lang to utf8 and it will work.