Ni(HO)2
High-Entropy Materials HEA Traditional Materials TRAMP-ID: mp-625072 · Space group: P3m1 (#156)
Basic Information
Formula
Ni(HO)2
MP-ID
mp-625072
Elements
3
Sites
5
Density
3.6219
g/cm³
Volume
42.50
ų
Cell a
3.3412
Å
Cell b
3.3412
Å
Cell c
4.3965
Å
α Angle
90.00
°
β Angle
90.00
°
γ Angle
120.00
°
Space Group
P3m1
Point Group
3m
Crystal System
Trigonal
Bravais Lattice
hP
Stability
No
Packing Fraction
0.7405
X-ray Diffraction
Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å
Diffraction Peaks (Top 16)
| 2θ | d (Å) | I | hkl |
|---|---|---|---|
| 20.20 | 4.3965 | 100.0 | (0,0,0,1) |
| 30.90 | 2.8935 | 39.7 | (1,0,-1,0) |
| 37.20 | 2.4170 | 98.8 | (1,0,-1,1) |
| 41.06 | 2.1983 | 4.4 | (0,0,0,2) |
| 52.26 | 1.7504 | 47.4 | (1,0,-1,2) |
| 54.96 | 1.6706 | 30.3 | (2,-1,-1,0) |
| 59.16 | 1.5616 | 27.3 | (2,-1,-1,1) |
| 63.48 | 1.4655 | 1.5 | (0,0,0,3) |
| 64.40 | 1.4468 | 5.1 | (2,0,-2,0) |
| 68.25 | 1.3743 | 14.1 | (2,0,-2,1) |
| 70.85 | 1.3301 | 5.7 | (2,-1,-1,2) |
| 72.27 | 1.3074 | 15.6 | (1,0,-1,3) |
| 79.27 | 1.2085 | 12.0 | (2,0,-2,2) |
| 88.82 | 1.1017 | 3.7 | (2,-1,-1,3) |
| 89.08 | 1.0991 | 1.5 | (0,0,0,4) |
| 89.64 | 1.0937 | 4.3 | (3,-1,-2,0) |
Energy Properties
Formation Energy/atom
-1.00742
eV/atom
Energy/atom
-5.50069
eV/atom
Energy above Hull
0.2478
eV/atom
Uncorrected Energy
-4.7177
eV/atom
Volume/atom
8.50
ų
c/a Ratio
1.3159
Electronic Properties
Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV
Magnetic Properties
Magnetic
Yes
Total Mag. Moment
2.0000
μB
Mag. Ordering
FM
Mag. Sites
1
Magnetization/Volume
0.047050
μB/ų
Elastic Properties
Elastic data not available
Feature Analysis
Composition Overview
Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
H · 0.400
Element Family
Alkali-AlkEarth
Solute Fraction
0.600
Interstitial Fraction
0.000
High-Entropy Alloy Features
Composite Radar (normalized)
Element-Class Share
Mix Entropy ΔS/R
1.0549
HEA criterion (>1.0 = high entropy)
Mix Entropy ΔS
8.7706
J/mol·K
Ω Parameter
0.0000
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
61.502%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.6633
smaller = more stable mixing
VEC
4.000
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
0.000
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9602
SS Former
0
Phase Tendency
IM
Traditional Material Features
ROM Blended-Feature Radar
Rating & Classification
Tier
C
Score
0.249
Family
H-rich Multi-Component
Matrix Element
H · 0.400
Related Tasks
Citation & References
Materials Project Page
https://materialsproject.org/materials/mp-625072
Reference Citation
The crystal structure and related material properties of Ni(HO)2 were obtained from the Materials Project database (MP-ID: mp-625072, database version v2026.04.13).
Literature Citation
Horton, M.K., Huck, P., Yang, R.X. et al. Accelerated data-driven materials science with the Materials Project. Nat. Mater. 24, 1522–1532 (2025). https://doi.org/10.1038/s41563-025-02272-0
3D Crystal Structure Rendering
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Raw CIF Data
# generated using pymatgen
data_Ni(HO)2
_symmetry_space_group_name_H-M 'P 1'
_cell_length_a 3.34115602
_cell_length_b 3.34115602
_cell_length_c 4.39649200
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 120.00000045
_symmetry_Int_Tables_number 1
_chemical_formula_structural Ni(HO)2
_chemical_formula_sum 'Ni1 H2 O2'
_cell_volume 42.50406136
_cell_formula_units_Z 1
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
1 'x, y, z'
loop_
_atom_site_type_symbol
_atom_site_label
_atom_site_symmetry_multiplicity
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Ni Ni0 1 0.33333300 0.66666700 0.98853900 1.0
H H1 1 0.00000000 0.00000000 0.01702600 1.0
H H2 1 0.66666700 0.33333300 0.43025600 1.0
O O3 1 0.00000000 0.00000000 0.79065800 1.0
O O4 1 0.66666700 0.33333300 0.20725700 1.0
