Na3PO4

from The Collaborative International Dictionary of English v.0.48

Phosphate \Phos"phate\, n. (Chem.)
   A salt of phosphoric acid or a compound containing the
   phosphate radical group {-PO4}; as, trisodium phosphate
   ({Na3PO4}); triethyl phosphate ({(C2H5)3PO4}).
   [1913 Webster + PJC]