Overview: Nb₂I₂O₂

Structure info
Layer group	pmmn
Layer group number	46
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.205
Heat of formation [eV/atom]	-1.394
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.000

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.123	-0.000	0.000	Yes
2	0.000	3.493	0.000	Yes
3	-0.000	0.000	21.342	No

Lengths [Å]	4.123	3.493	21.342
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	46
Layer group	pmmn
Space group number (bulk in AA-stacking)	59
Space group (bulk in AA-stacking)	Pmmn
Point group	mmm
Inversion symmetry	Yes

Structure data
Formula	Nb2I2O2
Stoichiometry	ABC
Number of atoms	6
Unit cell area [Å2]	14.401
Thickness [Å]	5.797

Stability

Convex hull

I2Nb2O2 (2INbO-1)
Heat of formation [eV/atom]	-1.39
Energy above convex hull [eV/atom]	0.20

Monolayers from C2DB
Nb4O8 (4NbO2-1)	-2.42 eV/atom
Nb2O4 (2NbO2-1)	-2.38 eV/atom
NbO2 (1NbO2-1)	-2.37 eV/atom
NbO2 (1NbO2-2)	-2.35 eV/atom
NbO2 (1NbO2-3)	-2.20 eV/atom
Nb4IO7 (1INb4O7-1)	-2.19 eV/atom
Nb2I2O4 (2INbO2-1)	-2.09 eV/atom
Nb2O6 (2NbO3-1)	-2.07 eV/atom
Nb4O12 (4NbO3-1)	-1.83 eV/atom
Nb3I2O4 (1I2Nb3O4-1)	-1.75 eV/atom
Nb2O2 (2NbO-1)	-1.53 eV/atom
Nb2I2O2, (2INbO-1)	-1.39 eV/atom
Nb2I4O2 (2NbOI2-1)	-1.36 eV/atom
Nb2O2 (2NbO-2)	-1.30 eV/atom
Nb2O2 (2NbO-3)	-1.02 eV/atom
Nb2I2O (1OI2Nb2-1)	-0.77 eV/atom
Nb3I7O (1ONb3I7-1)	-0.74 eV/atom
Nb3I8 (1Nb3I8-1)	-0.54 eV/atom
Nb2I6 (2NbI3-1)	-0.42 eV/atom
Nb2I4 (2NbI2-1)	-0.37 eV/atom
Nb2I6 (2NbI3-2)	-0.36 eV/atom
NbI2 (1NbI2-1)	-0.18 eV/atom
NbI2 (1NbI2-2)	-0.12 eV/atom
NbI2 (1NbI2-3)	0.13 eV/atom
Nb2I2 (2INb-1)	0.14 eV/atom
Nb2I2 (2INb-2)	0.15 eV/atom

Bulk crystals from OQMD123
Nb2O5	-2.77 eV/atom
Nb8O16	-2.64 eV/atom
Nb3O3	-2.08 eV/atom
Nb4I4O8	-2.08 eV/atom
Nb2I4O2	-1.35 eV/atom
Nb2I6O2	-1.12 eV/atom
Nb4I16	-0.49 eV/atom
Nb2I6	-0.48 eV/atom
Nb2I10	-0.46 eV/atom
I8O20	-0.08 eV/atom
I4	0.00 eV/atom
Nb	0.00 eV/atom
O8	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-9.70

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	275.29	6.82	-0.00
yy	8.59	95.34	0.00
xy	0.00	0.00	17.75

Stiffness tensor eigenvalues
Eigenvalue 0	17.75 N/m
Eigenvalue 1	95.02 N/m
Eigenvalue 2	275.62 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	0.000
Direct band gap (PBE)	0.000
Fermi level wrt. vacuum (PBE)	-4.253

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Nb	1.69
1	Nb	1.69
2	O	-1.29
3	O	-1.29
4	I	-0.40
5	I	-0.40

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	8.322
Interband polarizability (y) [Å]	8.242
Interband polarizability (z) [Å]	0.584
Plasma frequency (x) [eV Å0.5]	6.439
Plasma frequency (y) [eV Å0.5]	12.187

Miscellaneous

Miscellaneous details
Unique ID	2INbO-1
Number of atoms	6
Number of species	3
Formula	Nb2I2O2
Reduced formula	NbIO
Stoichiometry	ABC
Unit cell area [Å2]	14.401
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/ABC/INbO/I2Nb2O2-246af91521d6
Old uid	I2Nb2O2-246af91521d6
Space group (bulk in AA-stacking)	Pmmn
Space group number (bulk in AA-stacking)	59
Point group	mmm
Inversion symmetry	Yes
Layer group number	46
Layer group	pmmn
2D Bravais type	Rectangular (op)
Thickness [Å]	5.797
Structure origin	original03-18
Band gap (PBE) [eV]	0.000

Miscellaneous details
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	4.764
Fermi level wrt. vacuum (PBE) [eV]	-4.253
minhessianeig	-9.695
Dynamically stable	No
Interband polarizability (x) [Å]	8.322
Interband polarizability (y) [Å]	8.242
Interband polarizability (z) [Å]	0.584
Plasma frequency (x) [eV Å0.5]	6.439
Plasma frequency (y) [eV Å0.5]	12.187
Energy [eV]	-42.224
Magnetic	No
Spin axis	z
Magnetic anisotropy energy, xz [meV/unit cell]	0.000
Magnetic anisotropy energy, yz [meV/unit cell]	0.000
Energy above convex hull [eV/atom]	0.205
Heat of formation [eV/atom]	-1.394