CaCu2(BiO4)2

High-Entropy Materials HEA

MP-ID: mp-1040991 · Space group: P2_1/c (#14)

Materials Project API

Basic Information

Formula

CaCu2(BiO4)2

MP-ID

mp-1040991

Elements

Sites

Density

5.7360

g/cm³

Volume

825.79

Å³

Cell a

9.1080

Cell b

6.7045

Cell c

13.5247

α Angle

89.14

β Angle

90.00

γ Angle

90.00

Space Group

P2_1/c

Point Group

2/m

Crystal System

Monoclinic

Bravais Lattice

Stability

Packing Fraction

X-ray Diffraction

Diffraction Pattern

Target / Radiation

X-axis: 2θ (°); Y-axis: relative intensity; Cu Kα ; λ=1.5418 Å

Diffraction Peaks (Top 24)

2θ	d (Å)	I	hkl
13.09	6.7616	12.7	(0,0,2)
16.33	5.4291	1.1	(1,0,2)
16.42	5.3990	10.5	(1,1,0)
17.61	5.0351	27.3	(1,1,1)
17.76	4.9935	22.8	(1,1,-1)
18.50	4.7966	3.0	(0,1,2)
18.78	4.7254	9.8	(0,1,-2)
19.49	4.5540	53.0	(2,0,0)
20.58	4.3158	62.3	(2,0,1)
20.93	4.2440	21.1	(1,1,2)
21.18	4.1945	38.5	(1,1,-2)
22.00	4.0400	11.1	(1,0,3)
23.55	3.7772	15.7	(2,0,2)
24.48	3.6368	25.4	(2,1,1)
24.59	3.6210	25.8	(2,1,-1)
25.59	3.4809	91.4	(1,1,3)
25.90	3.4399	42.7	(1,1,-3)
26.36	3.3808	95.7	(0,0,4)
27.00	3.3026	6.5	(2,1,2)
27.20	3.2791	43.1	(2,1,-2)
28.15	3.1695	2.6	(1,0,4)
28.37	3.1456	28.5	(1,2,0)
29.05	3.0734	100.0	(1,2,1)
29.24	3.0544	68.2	(1,2,-1)

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Energy Properties

Formation Energy/atom

-1.39913

eV/atom

Energy/atom

-5.82742

eV/atom

Energy above Hull

0.1955

eV/atom

Uncorrected Energy

-5.4047

eV/atom

Volume/atom

15.88

Å³

c/a Ratio

1.4849

Electronic Properties

Metallic

Metal

Band Gap

Direct Gap

CBM

N/A

Magnetic Properties

Magnetic

Total Mag. Moment

0.0019

μB

Mag. Ordering

Mag. Sites

Magnetization/Volume

0.000000

μB/Å³

Elastic Properties

Elastic data not available

Feature Analysis

Composition Overview

Element Composition (atomic fraction)

Composition Info

Major / Matrix Element

O · 0.615

Element Family

Metalloid-Nonmetal

Solute Fraction

0.385

Interstitial Fraction

0.000

High-Entropy Alloy Features

Composite Radar (normalized)

Element-Class Share

Mix Entropy ΔS/R

1.0720

HEA criterion (>1.0 = high entropy)

Mix Entropy ΔS

8.9127

J/mol·K

Ω Parameter

1.5362

Ω > 1.1 favors solid solution

Atomic Size Mismatch δr

50.506%

δr < 6.6% favors single-phase solid solution

Electronegativity Diff Δχ

0.8482

smaller = more stable mixing

VEC

5.077

valence electron concentration, affects phase stability

Mix Enthalpy ΔH_mix

-2.392

kJ/mol; negative = exothermic mixing

Entropy Norm

0.7733

SS Former

Phase Tendency

Related Tasks

Related computation task IDs (2)

aaachfyt aaacxlbb

Citation & References

Materials Project Page

https://materialsproject.org/materials/mp-1040991

Reference Citation

The crystal structure and related material properties of CaCu2(BiO4)2 were obtained from the Materials Project database (MP-ID: mp-1040991, 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_CaCu2(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.10796800
_cell_length_b   6.70452200
_cell_length_c   13.52471502
_cell_angle_alpha   89.14381347
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaCu2(BiO4)2
_chemical_formula_sum   'Ca4 Cu8 Bi8 O32'
_cell_volume   825.78872311
_cell_formula_units_Z   4
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  0.15932100  0.11977100  0.04027500  1.0
  Ca  Ca1  1  0.84067900  0.88022900  0.95972500  1.0
  Ca  Ca2  1  0.65932100  0.88022900  0.45972500  1.0
  Ca  Ca3  1  0.34067900  0.11977100  0.54027500  1.0
  Cu  Cu4  1  0.19147000  0.74713400  0.88149100  1.0
  Cu  Cu5  1  0.05051700  0.37550100  0.61694700  1.0
  Cu  Cu6  1  0.94948300  0.62449900  0.38305300  1.0
  Cu  Cu7  1  0.80853000  0.25286600  0.11850900  1.0
  Cu  Cu8  1  0.30853000  0.74713400  0.38149100  1.0
  Cu  Cu9  1  0.44948300  0.37550100  0.11694700  1.0
  Cu  Cu10  1  0.69147000  0.25286600  0.61850900  1.0
  Cu  Cu11  1  0.55051700  0.62449900  0.88305300  1.0
  Bi  Bi12  1  0.44945800  0.10032800  0.83541900  1.0
  Bi  Bi13  1  0.05054200  0.10032800  0.33541900  1.0
  Bi  Bi14  1  0.09461000  0.61213400  0.14328900  1.0
  Bi  Bi15  1  0.94945800  0.89967200  0.66458100  1.0
  Bi  Bi16  1  0.90539000  0.38786600  0.85671100  1.0
  Bi  Bi17  1  0.59461000  0.38786600  0.35671100  1.0
  Bi  Bi18  1  0.40539000  0.61213400  0.64328900  1.0
  Bi  Bi19  1  0.55054200  0.89967200  0.16458100  1.0
  O  O20  1  0.25782900  0.01850500  0.38702200  1.0
  O  O21  1  0.01378000  0.64514500  0.58882900  1.0
  O  O22  1  0.58109700  0.20894900  0.49094500  1.0
  O  O23  1  0.08109700  0.79105100  0.00905500  1.0
  O  O24  1  0.24217100  0.01850500  0.88702200  1.0
  O  O25  1  0.74217100  0.98149500  0.61297800  1.0
  O  O26  1  0.10055600  0.10387500  0.60617600  1.0
  O  O27  1  0.87670200  0.50833100  0.13797400  1.0
  O  O28  1  0.62329800  0.50833100  0.63797400  1.0
  O  O29  1  0.87469600  0.30697000  0.68459000  1.0
  O  O30  1  0.37469600  0.69303000  0.81541000  1.0
  O  O31  1  0.12329800  0.49166900  0.86202600  1.0
  O  O32  1  0.89944400  0.89612500  0.39382400  1.0
  O  O33  1  0.52055600  0.86420400  0.31275300  1.0
  O  O34  1  0.24780000  0.41724900  0.58492400  1.0
  O  O35  1  0.25220000  0.41724900  0.08492400  1.0
  O  O36  1  0.02055600  0.13579600  0.18724700  1.0
  O  O37  1  0.37670200  0.49166900  0.36202600  1.0
  O  O38  1  0.47944400  0.13579600  0.68724700  1.0
  O  O39  1  0.41890300  0.79105100  0.50905500  1.0
  O  O40  1  0.48622000  0.64514500  0.08882900  1.0
  O  O41  1  0.12530400  0.69303000  0.31541000  1.0
  O  O42  1  0.75782900  0.98149500  0.11297800  1.0
  O  O43  1  0.39944400  0.10387500  0.10617600  1.0
  O  O44  1  0.91890300  0.20894900  0.99094500  1.0
  O  O45  1  0.74780000  0.58275100  0.91507600  1.0
  O  O46  1  0.98622000  0.35485500  0.41117100  1.0
  O  O47  1  0.51378000  0.35485500  0.91117100  1.0
  O  O48  1  0.60055600  0.89612500  0.89382400  1.0
  O  O49  1  0.75220000  0.58275100  0.41507600  1.0
  O  O50  1  0.62530400  0.30697000  0.18459000  1.0
  O  O51  1  0.97944400  0.86420400  0.81275300  1.0

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