The crystal structure of phosphoric acid hemihydrate, H 3 PO 4 .1/2H 2 O
1969; International Union of Crystallography; Volume: 25; Issue: 4 Linguagem: Inglês
10.1107/s0567740869002950
ISSN1600-8650
AutoresA. D. Mighell, James P. Smith, W. E. Brown,
Tópico(s)Organophosphorus compounds synthesis
ResumoThe crystal structure of phosphoric acid hemihydrate, H3PO4.1⁄2H20, was determined from threedimensional Weissenberg data. Its crystals are monoclinic, with a=7.922+0.010, b= 12.987+0-020, c = 7.470 + 0.010/~, p= 109.9 _+ 0.1 °, space group P2x/a, and Z = 8. The structure was solved by vector methods and was then refined by full-matrix least-squares analysis. The two crystallographicaUy independent phosphoric acid molecules are geometrically very similar to each other. Each is approximately tetrahedral with the P-O bond length significantly shorter than the P-OH bonds. Each phosphoryl oxygen atom, moreover, is the acceptor in two strong hydrogen bonds. The phosphoric acid and water molecules are linked into a three-dimensional network by hydrogen bonding, with each oxygen atom participating in at least one relatively strong intermolecular hydrogen bond.
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