Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: ABC2_oI8_44_a_a_c-001

This structure originally had the label ABC2_oI8_44_a_a_c. Calls to that address will be redirected here.

If you are using this page, please cite:
D. Hicks, M.J. Mehl, M. Esters, C. Oses, O. Levy, G.L.W. Hart, C. Toher, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 3, Comp. Mat. Sci. 199, 110450 (2021). (doi=10.1016/j.commatsci.2021.110450)

Links to this page

https://aflow.org/p/JZVB
or https://aflow.org/p/ABC2_oI8_44_a_a_c-001
or PDF Version

Ferroelectric NaNO$_{2}$ ($F5_{5}$) Structure: ABC2_oI8_44_a_a_c-001

Picture of Structure; Click for Big Picture
Prototype NaNO$_{2}$
AFLOW prototype label ABC2_oI8_44_a_a_c-001
Strukturbericht designation $F5_{5}$
Mineral name sodium nitrite
ICSD 15400
Pearson symbol oI8
Space group number 44
Space group symbol $Imm2$
AFLOW prototype command aflow --proto=ABC2_oI8_44_a_a_c-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak z_{1}, \allowbreak z_{2}, \allowbreak x_{3}, \allowbreak z_{3}$

Other compounds with this structure

AgNO$_{3}$ ($F5_{12}$)


  • This is the low-temperature phase of NaNO$_{2}$, ferroelectric below 158°C.
  • (Kay, 1961) gives the structure in the $Im2m$ setting of space group #44. We have used FINDSYM to put it in the standard $Imm2$ setting.
  • This structure is very similar to silver nitrite, AgNO$_{2}$, $F5_{12}$. We present both structures as they are listed separately in the Strukturbericht volumes.
  • The original publications give Wyckoff positions giving NaNO$_{2}$ the AFLOW prototype label ABC2_oI8_44_a_a_c and AgNO$_{2}$ the label ABC2_oI8_44_a_a_d. When we apply our AFLOW prototype label rules, however, the label for both structures becomes ABC2_oI8_44_a_a_c. The two structures are generated by the same symmetry operations with different sets of parameters (--params) specified in their corresponding CIF files.
  • The origin of the $z$ coordinate in $Imm2$, or the $y$ coordinate in $Im2m$, is arbitrary. Here $z_{3}$ is set to zero.

\[ \begin{array}{ccc} \mathbf{a_{1}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}- \frac{1}{2}c \,\mathbf{\hat{z}} \end{array}\]

Basis vectors

Lattice coordinates Cartesian coordinates Wyckoff position Atom type
$\mathbf{B_{1}}$ = $z_{1} \, \mathbf{a}_{1}+z_{1} \, \mathbf{a}_{2}$ = $c z_{1} \,\mathbf{\hat{z}}$ (2a) N I
$\mathbf{B_{2}}$ = $z_{2} \, \mathbf{a}_{1}+z_{2} \, \mathbf{a}_{2}$ = $c z_{2} \,\mathbf{\hat{z}}$ (2a) Na I
$\mathbf{B_{3}}$ = $z_{3} \, \mathbf{a}_{1}+\left(x_{3} + z_{3}\right) \, \mathbf{a}_{2}+x_{3} \, \mathbf{a}_{3}$ = $a x_{3} \,\mathbf{\hat{x}}+c z_{3} \,\mathbf{\hat{z}}$ (4c) O I
$\mathbf{B_{4}}$ = $z_{3} \, \mathbf{a}_{1}- \left(x_{3} - z_{3}\right) \, \mathbf{a}_{2}- x_{3} \, \mathbf{a}_{3}$ = $- a x_{3} \,\mathbf{\hat{x}}+c z_{3} \,\mathbf{\hat{z}}$ (4c) O I

References

  • M. I. Kay and B. C. Frazier, A neutron diffraction refinement of the low temperature phase of NaNO$_{2}$, Acta Cryst. 14, 56–57 (1961), doi:10.1107/S0365110X61000103.

Prototype Generator

aflow --proto=ABC2_oI8_44_a_a_c --params=$a,b/a,c/a,z_{1},z_{2},x_{3},z_{3}$

Species:

Running:

Output: