Esterification of glycerin at one of the terminal
alcohol groups with phosphoric acid leads to
phosphoglycerin or phosphoglycerol.
Phosphaglycerin is the "backbone" of phosphatidic acids.
Phosphatidic acids are triesters formed between
glycerin, one OP(OH)3 molecule (at a terminal OH group) and two
fatty acids. Note that C2-carbon is chiral and should have the
R-configuration.