Facebook founder Mark Zuckerberg and wife Priscilla Chan are among the 50 "most generous" donors of 2012, according to a new list.

The Chronicle of Philanthropy revealed that Zuckerberg, 28, and Chan, 27, donated nearly $500 million to the Silicon Valley Community Foundation, a nonprofit organization that works with donors to manage their contributions. The couple gave 18 million shares of Facebook stock — valued at $498.8 million — to the foundation to support education and health programs.

Zuckerberg announced his donation via Facebook last December. In the post, the billionaire said that he and Chan, a pediatrician, committed to donating most of the money they earn to charity. In 2010, Zuckerberg pledged $100 million to establish Startup: Education, an organization that aims to build a "better education system" for students.

Their hefty donation pushed Zuckerberg and Chan to second place on the list — but that still wasn't enough to eclipse business magnate Warren Buffett, who donated $3.1 billion to each of his three children's foundations: the Howard G. Buffett Foundation, the NoVo Foundation and the Sherwood Foundation. Buffett, 82, pledged 12,220,852 shares of Berkshire Hathaway class "B" stock.

Google co-founder Sergey Brin and wife Anne Wojcicki came in fifth place on the Philanthropy list after donating around $222.9 million. Brin and Wojcicki, both 39, gave $190.1 million to the Brin Wojcicki Foundation, a charity that they started. The couple also contributed $32.8 million to the Michael J. Fox Foundation for Parkinson's Research.

Rounding out the top five are Microsoft co-founder Paul Allen and financiers John and Laura Arnold.

Image courtesy of Facebook, Mark Zuckerberg