English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The isovalent substitution of chromium for aluminium at octahedral site along the Na(Al 1- x  Cr  x  )P 2 O 7  pyrophosphate solid solution has been investigated by means of the combined application of X-ray powder diffraction (XRPD) and electronic absorption spectroscopy (EAS). In agreement with the structural refinements, deconvolution of the optical spectra revealed a progressive decreasing of the crystal field strength parameter 10 Dq  moving toward the NaCrP 2 O 7  end-member, meaning that the local chromium–oxygen bond distance increased along the join with the amount of chromium. The calculated structural relaxation coefficient around the substituent ion Cr 3+  was  ε =0.97 (i.e., very close to that predicted by the Hard Spheres model). A detailed comparison with compact crystal structures (i.e., perovskite, garnet, spinel, clinopyroxene, and corundum) as well as with other pyrophosphate compounds with II-Na M P 2 O 7  structure-type (with  M =Al, Cr, Fe, V, Ti, Mo and In) highlighted that compounds belonging to the Na(Al 1- x  Cr  x  )P 2 O 7  solid solution – characterized by a network connectivity which is basically a framework topology – undergo a structural relaxation that is confined within the first shell (i.e., occurs at the octahedral site), while P 2 O 7  dimers act as rigid units.

Structural relaxation around Cr 3+ at the Na(Al 1- x Cr x )P 2 O 7 octahedral site: an XRPD and EAS study