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Crystal Structure of Ammonium Catena ‐polyphosphate IV [NH 4 PO 3 ] x
Author(s) -
Sedlmaier Stefan J.,
Schnick Wolfgang
Publication year - 2008
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800055
Subject(s) - monoclinic crystal system , polyphosphate , crystal structure , crystallography , chemistry , ammonium polyphosphate , hydrogen bond , ammonium , ammonia , crystal twinning , crystal (programming language) , inorganic chemistry , molecule , phosphate , fire retardant , organic chemistry , microstructure , computer science , programming language
Phase‐pure ammonium catena ‐polyphosphate IV [NH 4 PO 3 ] x was synthesized by heating NH 4 H 2 PO 4 in a tube furnace under an ammonia gas flow. The product contained single crystals of [NH 4 PO 3 ] x IV appropriate for an X‐ray structure determination enabling structure refinement of this compound. The pseudo‐merohedrally twinned crystals of [NH 4 PO 3 ] x crystallize in the monoclinic crystal system ( P 2 1 / c , no. 14, a = 2270.3(5), b = 458.14(9), c = 1445.1(3) pm, β = 108.56(3)°, Z = 4, 2264 data, R 1 = 0.076). In the unit cell the catena ‐polyphosphate chain anions run parallel [010] with a chain‐periodicity P = 2 and a stretching factor f s = 0.94. The chain anions are interconnected through extensive hydrogen bonding towards the ammonium ions. Due to ‘chemical twinning’ a novel catena ‐polyphosphate structure type is realized in [NH 4 PO 3 ] x IV. The vibrational spectra of [NH 4 PO 3 ] x IV are reported as well.