TY - JOUR
T1 - Synthesis and structure of a calcium polyphosphate with a unique cross-cross arrangements of helical phosphate chains
AU - [No Value], [No Value]
AU - Kariuki, Benson
AU - Smith, ME
AU - Barralet, JE
AU - Wright, Adrian
PY - 2005/9/6
Y1 - 2005/9/6
N2 - We report here the facile synthesis and structural characterization of gamma-Ca(PO3)2, a novel polymorph of calcium polyphosphate. The single-step synthesis of this potential biomaterial was achieved using flux methods at 250 degrees C, yielding a single-phase product stable at room temperature. Single-crystal X-ray diffraction determined the structure to be of monoclinic symmetry (a = 9.5669(2) angstrom, b = 9.5023(2) angstrom, c = 10.3717(3) angstrom, and beta = 93.474(2)degrees, space group Cc), with layers of helical polyphosphate chains directed alternately along the [110] and [110] unit cell directions to produce a unique arrangement of criss-cross polyphosphate layers separated by calcium ions. Further structural characterization by MAS-NMR and FT-IR was found to be consistent with this structure. Thermal studies indicated that gamma-Ca(PO3)(2) is stable up to 690 degrees C, whereupon it irreversibly converts to the P-Ca(PO3)(2) polymorph.
AB - We report here the facile synthesis and structural characterization of gamma-Ca(PO3)2, a novel polymorph of calcium polyphosphate. The single-step synthesis of this potential biomaterial was achieved using flux methods at 250 degrees C, yielding a single-phase product stable at room temperature. Single-crystal X-ray diffraction determined the structure to be of monoclinic symmetry (a = 9.5669(2) angstrom, b = 9.5023(2) angstrom, c = 10.3717(3) angstrom, and beta = 93.474(2)degrees, space group Cc), with layers of helical polyphosphate chains directed alternately along the [110] and [110] unit cell directions to produce a unique arrangement of criss-cross polyphosphate layers separated by calcium ions. Further structural characterization by MAS-NMR and FT-IR was found to be consistent with this structure. Thermal studies indicated that gamma-Ca(PO3)(2) is stable up to 690 degrees C, whereupon it irreversibly converts to the P-Ca(PO3)(2) polymorph.
UR - http://www.scopus.com/inward/record.url?scp=25444502668&partnerID=8YFLogxK
U2 - 10.1021/cm050984x
DO - 10.1021/cm050984x
M3 - Article
SN - 1520-5002
VL - 17
SP - 4642
EP - 4646
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 18
ER -