Charge states of Ca atoms in β-dicalcium silicate

Kazuhiro Mori, Ryoji Kiyanagi, Masao Yonemura, Kenji Iwase, Takashi Sato, Keiji Itoh, Masaaki Sugiyama, Takashi Kamiyama, Toshiharu Fukunaga

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


In order to study the crystal structure of β - Ca2 SiO4, time-of-flight neutron powder diffraction experiments were carried out at temperatures between room temperature (RT) and 600 °C. Rietveld refinement at RT has shown that β - Ca2 SiO4 is monoclinic based on P21/n symmetry and two different types of Ca sites, Ca(1) and Ca(2). All interatomic distances within 3 Å were calculated, with the valences of Ca(1) with seven Ca{single bond}O bonds and Ca(2) with eight were estimated to be 1.87+ and 2+ by the Zachariasen-Brown-Altermatt formula (bond valence sum). Applying charge neutrality the two charge states of Ca in β - Ca2 SiO4 are [Ca(1)SiO4]2- and Ca(2)2+, respectively. Furthermore, the [Ca(1)SiO4]2- unit has the shortest Ca-O distance, and its length kept constant at 2.23 Å at all temperatures. In the short-range structure analysis at RT, the shortest Ca-O bond was also observed in a radial distribution function. These results imply that the [Ca(1)SiO4]2- unit has covalency on the shortest Ca-O in addition to Si-O.

Original languageEnglish
Pages (from-to)3286-3294
Number of pages9
JournalJournal of Solid State Chemistry
Issue number11
Publication statusPublished - Nov 2006
Externally publishedYes


  • Bond valence sum
  • Crystal structure
  • Neutron powder diffraction
  • Radial distribution function
  • Rietveld analysis
  • Short-range structure
  • β - Ca SiO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


Dive into the research topics of 'Charge states of Ca atoms in β-dicalcium silicate'. Together they form a unique fingerprint.

Cite this