Air Products and Chemicals launched an unsolicited $5.1-billion cash bid to buy rival Airgas Friday in a move to create the largest industrial gas company in North America. Airgas shares jumped 42 percent in premarket trading.

Air Products, which supplies gases such as argon, helium and nitrogen to industrial users in the metals, chemicals and pharmaceuticals sectors, said the deal would be an immediate boost to its earnings and yield cost savings of $250 million.

The total deal value of $7 billion includes $5.1 billion of equity and $1.9 billion of assumed debt.

Airgas, which has a large sales and distribution network that sells canisters of specialty gases to industrial and medical facilities, said its board of directors would review the proposal. It advised its shareholders to take no action.