Ferroelectric NaNO2 ($F5_{5}$) Structure : ABC2_oI8_44_a_a_c

Picture of Structure; Click for Big Picture
Prototype : NaNO2
AFLOW prototype label : ABC2_oI8_44_a_a_c
Strukturbericht designation : $F5_{5}$
Pearson symbol : oI8
Space group number : 44
Space group symbol : $Imm2$
AFLOW prototype command : aflow --proto=ABC2_oI8_44_a_a_c
--params=
$a$,$b/a$,$c/a$,$z_{1}$,$z_{2}$,$x_{3}$,$z_{3}$


Other compounds with this structure

  • AgNO2 ($F5_{12}$)

  • This is the low–temperature phase of NaNO2. It is 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, AgNO2, $F5_{12}$. We list the two structures as they are listed separately in the Strukturbericht volumes.
  • The origin of the $z$ coordinate in $Imm2$, or the $y$ coordinate in $Im2m$, is arbitrary, and $z_{3}$ is set to zero.

Body-centered Orthorhombic primitive vectors:

\[ \begin{array}{ccc} \mathbf{a}_1 & = & - \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, b \, \mathbf{\hat{y}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_2 & = & ~ \frac12 \, a \, \mathbf{\hat{x}} - \frac12 \, b \, \mathbf{\hat{y}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_3 & = & ~ \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, b \, \mathbf{\hat{y}} - \frac12 \, c \, \mathbf{\hat{z}} \\ \end{array} \]

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & = & z_{1} \, \mathbf{a}_{1} + z_{1} \, \mathbf{a}_{2} & = & z_{1}c \, \mathbf{\hat{z}} & \left(2a\right) & \mbox{N} \\ \mathbf{B}_{2} & = & z_{2} \, \mathbf{a}_{1} + z_{2} \, \mathbf{a}_{2} & = & z_{2}c \, \mathbf{\hat{z}} & \left(2a\right) & \mbox{Na} \\ \mathbf{B}_{3} & = & z_{3} \, \mathbf{a}_{1} + \left(x_{3}+z_{3}\right) \, \mathbf{a}_{2} + x_{3} \, \mathbf{a}_{3} & = & x_{3}a \, \mathbf{\hat{x}} + z_{3}c \, \mathbf{\hat{z}} & \left(4c\right) & \mbox{O} \\ \mathbf{B}_{4} & = & z_{3} \, \mathbf{a}_{1} + \left(-x_{3}+z_{3}\right) \, \mathbf{a}_{2}-x_{3} \, \mathbf{a}_{3} & = & -x_{3}a \, \mathbf{\hat{x}} + z_{3}c \, \mathbf{\hat{z}} & \left(4c\right) & \mbox{O} \\ \end{array} \]

References

  • M. I. Kay and B. C. Frazier, A neutron diffraction refinement of the low temperature phase of NaNO2, Acta Cryst. 14, 56–57 (1961), doi:10.1107/S0365110X61000103.

Geometry files


Prototype Generator

aflow --proto=ABC2_oI8_44_a_a_c --params=

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