Encyclopedia of Crystallographic Prototypes

True Low Nasicon (Na$_{3}$Zr$_{2}$Si$_{2}$PO$_{12}$) Structure: A6B12CD2E2_mC92_15_ae2f_6f_e_f_f-001

• Nasicon-type materials form the backbone of many ionic conductors. The current composition, referred to as true nasicon by (Boilot, 1987) is similar to the original nasicon found by (Hong, 1976). There are many related structures which we hope to address in the future.
• This is the room temperature structure of nasicon. At higher temperatures it transforms into rhombohedral high nasicon.
• (Boilot, 1987) give the data for low nasicon in the $B2/b$ unique axis c setting of space group #15. The AFLOW prototype label protocol changes this to the standard $C2/c$ unique axis b setting, moving the Na I atoms from the (4c) to the (4a) Wyckoff position while doing a rearrangement of the primitive vectors.
• As with all nasicon structures, there is considerable disorder:
  • The Na I (4a) sites is 22% occupied.
  • The Na III (8f) site is 56% occupied.
  • The Na IV (8f) site is 39% occupied.
  • The P (4e) and Si (8f) sites are both actually Si$_{0.7}$P$_{0.3}$. We arbitarily split them as shown.
• These occupations make the true stoichiometry of the crystal Na$_{3.12}$Zr$_{2}$Si$_{2.12}$P$_{0.88}$O$_{12}$.

Base-centered Monoclinic primitive vectors

References

• J. P. Boilot, G. Collin, and P. Colomban, Crystal structure of the true nasicon: Na$_{3}$Zr$_{2}$Si$_{2}$PO$_{12}$, Mater. Res. Bull. 22, 669–676 (1987), doi:10.1016/0025-5408(87)90116-4.
• H. Y.-P. Hong, Crystal structures and crystal chemistry in the system Na$_{1+x}$Zr$_{2}$Si$_{x}$P$_{3-x}$O$_{12}$, Mater. Res. Bull. 11, 173–182 (1976), doi:10.1016/0025-5408(76)90073-8.

First cited in

• N. Anderson, M. J. Mehl, H. Eckert, S. Divilov, X. Campilongo, S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 5. Submitted to Computational Materials Science (2026).

Geometry files

• CIF

Species:

Running:

Output: