Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: A4B2C_tI14_139_ce_e_a-001

This structure originally had the label A4B2C_tI14_139_ce_e_a. 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)

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https://aflow.org/p/SENW
or https://aflow.org/p/A4B2C_tI14_139_ce_e_a-001
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K $_{2}$ NiF $_{4}$ Structure: A4B2C_tI14_139_ce_e_a-001

Prototype	F $_{4}$ K $_{2}$ Ni
AFLOW prototype label	A4B2C_tI14_139_ce_e_a-001
ICSD	15576
Pearson symbol	tI14
Space group number	139
Space group symbol	$I 4/ mmm$
AFLOW prototype command	aflow --proto=A4B2C_tI14_139_ce_e_a-001 --params= $a, c / a, z_{3}, z_{4}$

View the structure from several different perspectives
View the primitive and conventional cell

Other compounds with this structure

Ba $_{2}$ SnO $_{4}$ , Ca $_{2}$ MnO $_{4}$ , Cs $_{2}$ CrCl $_{4}$ , Cs $_{2}$ CrF $_{4}$ , Cs $_{2}$ CuCl $_{4}$ , Cs $_{2}$ CuF $_{4}$ , K $_{2}$ CrCl $_{4}$ , K $_{2}$ CrF $_{4}$ , K $_{2}$ CuCl $_{4}$ , K $_{2}$ CuF $_{4}$ , La $_{2}$ NiO $_{4}$ , La $_{2}$ PdO $_{4}$ , Nd $_{2}$ CuO $_{4}$ , Sr $_{2}$ IrO $_{4}$ , Sr $_{2}$ MnO $_{4}$ , Sr $_{2}$ RuO $_{4}$ , Sr $_{2}$ SnO $_{4}$ , Sr $_{2}$ TiO $_{4}$ , Sr $_{2}$ VO $_{4}$ , (Fe, La) $_{2}$ SrO $_{4}$ , (Sr, La) $_{2}$ AlO $_{4}$ , (Sr, La) $_{2}$ CoO $_{4}$

This is the parent compound of the simplest layered-perovskite Ruddlesden-Popper series (Wikipedia). The series also includes the parent of the high- $T_{c}$ cuprates, (La,Ba) $_{2}$ CuO $_{4}$ , but we keep that separate as it represents a new class of materials.
Sr $_{2}$ CuO $_{2}$ Cl $_{2}$ is the quaternary form of this structure.

Body-centered Tetragonal primitive vectors

a_{1} a_{2} a_{3} = = = - \frac{1}{2} a \hat{x} + \frac{1}{2} a \hat{y} + \frac{1}{2} c \hat{z} \frac{1}{2} a \hat{x} - \frac{1}{2} a \hat{y} + \frac{1}{2} c \hat{z} \frac{1}{2} a \hat{x} + \frac{1}{2} a \hat{y} - \frac{1}{2} c \hat{z}

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Basis vectors

		Lattice coordinates		Cartesian coordinates	Wyckoff position	Atom type
$B_{1}$	=	$0$	=	$0$	(2a)	Ni I
$B_{2}$	=	$\frac{1}{2} a_{1} + \frac{1}{2} a_{3}$	=	$\frac{1}{2} a \hat{y}$	(4c)	F I
$B_{3}$	=	$\frac{1}{2} a_{2} + \frac{1}{2} a_{3}$	=	$\frac{1}{2} a \hat{x}$	(4c)	F I
$B_{4}$	=	$z_{3} a_{1} + z_{3} a_{2}$	=	$c z_{3} \hat{z}$	(4e)	F II
$B_{5}$	=	$- z_{3} a_{1} - z_{3} a_{2}$	=	$- c z_{3} \hat{z}$	(4e)	F II
$B_{6}$	=	$z_{4} a_{1} + z_{4} a_{2}$	=	$c z_{4} \hat{z}$	(4e)	K I
$B_{7}$	=	$- z_{4} a_{1} - z_{4} a_{2}$	=	$- c z_{4} \hat{z}$	(4e)	K I

References

D. Balz and K. Pleith, Die Struktur des Kaliumnickelfluorids, K $_{2}$ NiF $_{4}$ , Z. Elektrochemie 59, 545–551 (1955).

Found in

S. N. Ruddlesden and P. Popper, New compounds of the K $_{2}$ NiF $_{4}$ type, Acta Cryst. 10, 538–539 (1957), doi:10.1107/S0365110X57001929.

a

c / a

z_{3}

z_{4}

A

B

C

Encyclopedia of Crystallographic Prototypes

K $_{2}$ NiF $_{4}$ Structure: A4B2C_tI14_139_ce_e_a-001

Body-centered Tetragonal primitive vectors

References

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Encyclopedia of Crystallographic Prototypes

K2​NiF4​ Structure: A4B2C_tI14_139_ce_e_a-001

Body-centered Tetragonal primitive vectors

References

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K $_{2}$ NiF $_{4}$ Structure: A4B2C_tI14_139_ce_e_a-001