Sentence:  The bond angles and distances are all within the expected limits and the volume per <WSD>oxygen</WSD> is about normal . 
Meaning of the word marked with <WSD> tags:  a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust