Deals of the day- Mergers and acquisitions
(Adds Colbun, Nexen Energy, Griffin Real Estate, Zinjin, Amer Sports, Sterigenics; updates Tenet, Ivanhoe Mines, Humana))
March 23 (Reuters) - The following bids, mergers, acquisitions and disposals were reported by 2000 GMT on Monday:
** China National Chemical Corp (ChemChina) is to buy Pirelli, the world's fifth-largest tyre maker, in a 7.1 billion euro ($7.7 billion) deal that will place one of the symbols of Italy's manufacturing industry in Chinese hands.
** Royal Bank of Scotland is to sell up to $3.3 billion more shares in its U.S. bank Citizens to cut its stake to less than half and accelerate its retreat to its home UK market.
** Private equity firm Warburg Pincus LLC has agreed to acquire a majority stake in Sterigenics International LLC in a deal that values the U.S. provider of contract sterilization services at more than $2 billion, including debt, a source familiar with the transaction said.