It is a conjugate base of a phosphonic acid. It is a conjugate acid of a phosphonate(2-). Metaphosphoric acid (HPO3) Basic Attributes Molecular Weight: 79.98 Exact Mass: 79.98 EC Number: 253-433-4 Characteristics PSA: 54.4 XLogP3: 0.06660 Appearance: Clear pieces Water Solubility...