New isostructural ethylenediammonium diphosphates (NH3(CH 2)2NH3)2[Me(HP2O 7)2·2 H2O] [Me = Co, Ni]: X-ray crystal structure and vibrational spectroscopy

Francesco Capitelli, Brahim El Bali, Rachid Essehli, Mohammed Lachkar, Veronica Valentini, Giorgio Mattei, Jan Taraba, Zdirak Zak

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New ethylenediammonium diphosphates (NH3(CH2) 2NH3)2[Me(HP2O7) 2·2 H2O] [Me = Co (1), Ni (2)] have been synthesized and investigated by single-crystal X-ray diffractometry. The two structures resulted to be isostructural within triclinic space group P1. The unit-cell parameters are: a = 7.5211(6) Å, b = 7.5574(3) Å, c = 9.7689(7) Å, α = 103.6(1)°, β = 111.14(1)°, γ = 98.04(1)°, V = 486.9(1) Å3 (1) and a = 7.4631(15) Å, b = 7.5274(12) Å, c = 9.743(3) Å, α = 104.28(2)°, β = 110.75(2)°, γ = 97.50(2)°, V = 481.4(2) Å3 (2). The three-dimensional network is built up by discrete Me(HP2O 7)2·2 H2O moieties, which, via strong O-H . . . O bonds, form layers parallel to ab plane. Ethylenediammonium groups are located between such layers, stabilizing the framework via N-H . . . O bonds. The hydrogendiphosphate group presents bent eclipsed conformation, while the Me ion lies on inversion centre. The structural data, as the bent POP configuration, have been confirmed by the Raman and infrared spectra of the title compounds. In particular, the non-coincidence between the infrared and Raman bands supports the centrosymmetric structure of the investigated crystals.

Original languageEnglish
Pages (from-to)649-655
Number of pages7
JournalZeitschrift fur Kristallographie
Issue number9
Publication statusPublished - 18 Sep 2006



  • Diphosphate
  • Ethylenediammonium
  • Raman and infrared spectroscopy
  • Single crystal structure analysis
  • X-ray diffraction

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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