Iron(II) hydroxide
Iron(II) hydroxide or ferrous hydroxide is an inorganic compound with the formula Fe(OH). It is produced when iron(II) salts, from a compound such as iron(II) sulfate, are treated with hydroxide ions. Iron(II) hydroxide is a white solid, but even traces of oxygen impart a greenish tinge. The air-oxidized solid is sometimes known as "green rust".
Ticker symbol
Symbols sometimes change to reflect mergers. Prior to the 1999 merger with Mobil Oil, Exxon used a phonetic spelling of the company "XON" as its ticker symbol. The symbol of the firm after the merger was "XOM". Symbols are sometimes reused. In the US the single-letter symbols are particularly sought after as vanity symbols. For example, since Mar 2008 Visa Inc. has used the symbol V that had previously been used by Vivendi which had delisted and given up the symbol.