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Ca(AgGe)2

High-Entropy Materials HEA Traditional Materials TRA Elasticity Data ELA

MP-ID: mp-7878 · Space group: I4/mmm (#139)

Basic Information

Formula
Ca(AgGe)2
MP-ID
mp-7878
Elements
3
Sites
5
Density
6.5383
g/cm³
Volume
101.87
ų
Cell a
4.3208
Å
Cell b
4.3208
Å
Cell c
6.2536
Å
α Angle
110.21
°
β Angle
110.21
°
γ Angle
90.00
°
Space Group
I4/mmm
Point Group
4/mmm
Crystal System
Tetragonal
Bravais Lattice
Tetragonal I
Stability
No
Packing Fraction
0.7400

X-ray Diffraction

Diffraction Pattern
X-axis: 2θ (°); Y-axis: relative intensity; CuKa ; λ=1.5406 Å
Diffraction Peaks (Top 24)
2θd (Å)Ihkl
16.24 5.4564 78.1 (0,0,1)
22.13 4.0174 35.1 (1,0,0)
29.23 3.0553 1.7 (1,-1,0)
32.17 2.7828 33.5 (1,0,1)
32.83 2.7282 10.0 (0,0,2)
33.62 2.6658 50.0 (1,-1,-1)
33.62 2.6658 100.0 (1,-1,1)
33.62 2.6658 50.0 (1,1,-2)
41.81 2.1604 53.5 (0,2,-1)
41.81 2.1604 53.5 (2,0,-1)
44.52 2.0350 26.7 (1,-1,-2)
44.52 2.0350 53.4 (1,1,1)
44.52 2.0350 26.7 (1,1,-3)
45.14 2.0087 5.8 (0,2,0)
45.14 2.0087 17.4 (2,0,-2)
46.62 1.9481 23.0 (1,0,2)
46.62 1.9481 7.7 (0,1,-3)
47.80 1.9027 3.6 (1,-2,0)
47.80 1.9027 2.4 (2,-1,0)
47.80 1.9027 3.6 (2,1,-1)
50.16 1.8188 12.6 (0,0,3)
53.71 1.7065 3.7 (1,-2,-1)
53.71 1.7065 7.3 (2,-1,1)
53.71 1.7065 3.7 (2,1,-3)
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Energy Properties

Formation Energy/atom
-0.32485
eV/atom
Energy/atom
-15.82365
eV/atom
Energy above Hull
0.0084
eV/atom
Uncorrected Energy
-15.8237
eV/atom
Volume/atom
20.37
ų
c/a Ratio
1.4473

Electronic Properties

Metallic
Metal
Band Gap
0
eV
Direct Gap
No
CBM
N/A
eV

Magnetic Properties

Magnetic
Yes
Total Mag. Moment
0.0000
μB
Mag. Ordering
Unknown
Mag. Sites
0
Magnetization/Volume
0.000000
μB/ų

Elastic Properties

KVRH
64.213
GPa
GVRH
26.011
GPa
Young's Modulus E
68.750
GPa
Poisson Ratio ν
0.322
Pugh Ratio K/G
2.469
Vickers Hardness Est.
1.674
GPa
Ductility
Brittle
Anisotropy
0.379
Lame λ
46.872
GPa

Feature Analysis

Composition Overview

Element Composition (atomic fraction)
Composition Info
Major / Matrix Element
Ag · 0.400
Element Family
4d-TM
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
0.2988
Ω > 1.1 favors solid solution
Atomic Size Mismatch δr
17.962%
δr < 6.6% favors single-phase solid solution
Electronegativity Diff Δχ
0.3896
smaller = more stable mixing
VEC
6.400
valence electron concentration, affects phase stability
Mix Enthalpy ΔH_mix
-35.268
kJ/mol; negative = exothermic mixing
Entropy Norm
0.9602
SS Former
0
Phase Tendency
AM

Traditional Material Features

ROM Blended-Feature Radar
Rating & Classification
Tier
B
Score
0.627
Family
Ag-rich Multi-Component
Matrix Element
Ag · 0.400

Elasticity Features

Elastic Modulus Comparison (GPa)
Elastic Features
Elastic Anisotropy AU
0.3790
Homogeneous Poisson ν
0.3220
Debye Temperature
243.5
K
Sound Velocity
2,234.1
m/s
Homogeneity
0.3220

Related Tasks

Citation & References

Materials Project Page
https://materialsproject.org/materials/mp-7878
Reference Citation

The crystal structure and related material properties of Ca(AgGe)2 were obtained from the Materials Project database (MP-ID: mp-7878, 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

BibTeX
@article{Horton2025,
  author  = {Horton, Matthew K. and Huck, Patrick and Yang, Ruo Xi and Munro, Jason M. and Dwaraknath, Shyam and Ganose, Alex M. and Kingsbury, Ryan S. and Wen, Mingjian and Shen, Jimmy X. and Mathis, Tyler S. and Kaplan, Aaron D. and Berket, Karlo and Riebesell, Janosh and George, Janine and Rosen, Andrew S. and Spotte-Smith, Evan W. C. and McDermott, Matthew J. and Cohen, Orion A. and Dunn, Alex and Kuner, Matthew C. and Rignanese, Gian-Marco and Petretto, Guido and Waroquiers, David and Griffin, Sinead M. and Neaton, Jeffrey B. and Chrzan, Daryl C. and Asta, Mark and Hautier, Geoffroy and Cholia, Shreyas and Ceder, Gerbrand and Ong, Shyue Ping and Jain, Anubhav and Persson, Kristin A.},
  title   = {Accelerated data-driven materials science with the Materials Project},
  journal = {Nature Materials},
  year    = {2025},
  volume  = {24},
  number  = {10},
  pages   = {1522--1532},
  month   = {oct},
  doi     = {10.1038/s41563-025-02272-0},
  issn    = {1476-4660},
  url     = {https://doi.org/10.1038/s41563-025-02272-0},
  abstract = {The Materials Project was launched formally in 2011 to drive materials discovery forwards through high-throughput computation and open data. More than a decade later, the Materials Project has become an indispensable tool used by more than 600,000 materials researchers around the world. This Perspective describes how the Materials Project, as a data platform and a software ecosystem, has helped to shape research in data-driven materials science. We cover how sustainable software and computational methods have accelerated materials design while becoming more open source and collaborative in nature. Next, we present cases where the Materials Project was used to understand and discover functional materials. We then describe our efforts to meet the needs of an expanding user base, through technical infrastructure updates ranging from data architecture and cloud resources to interactive web applications. Finally, we discuss opportunities to better aid the research community, with the vision that more accessible and easy-to-understand materials data will result in democratized materials knowledge and an increasingly collaborative community.}
}

3D Crystal Structure Rendering

Loading 3D structure…

Style: Ball & Stick
Raw CIF Data
# generated using pymatgen
data_Ca(AgGe)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.32077717
_cell_length_b   4.32077754
_cell_length_c   6.25357049
_cell_angle_alpha   110.21015399
_cell_angle_beta   110.21016665
_cell_angle_gamma   90.00001726
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca(AgGe)2
_chemical_formula_sum   'Ca1 Ag2 Ge2'
_cell_volume   101.86667126
_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
  Ca  Ca0  1  -0.00000000  -0.00000000  0.00000000  1.0
  Ag  Ag1  1  0.75000000  0.25000000  0.50000000  1.0
  Ag  Ag2  1  0.25000000  0.75000000  0.50000000  1.0
  Ge  Ge3  1  0.39030713  0.39030713  0.78061526  1.0
  Ge  Ge4  1  0.60969287  0.60969287  0.21938474  1.0
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