Air Products & Chemicals posted a sharp drop in quarterly profit on Friday, partly due to weak demand for a solar product, and the industrial gas producer said its chief financial officer will retire.

For the fourth quarter ended Sept. 30, the company posted net income of $138.7 million, or 64 cents per share, compared with $324.8 million, or $1.51 per share, a year earlier.

Revenue rose 4% to $2.61 billion.

For the October-through-December quarter, Air Products expects to earn $1.26 to $1.31 per share.