ELATE: Elastic tensor analysis

Welcome to ELATE, the online tool for analysis of elastic tensors, developed by Romain Gaillac and Fran├žois-Xavier Coudert at CNRS / Chimie ParisTech.
If you use the software in published results (paper, conference, etc.), please cite the corresponding paper (J. Phys. Condens. Matter, 2016, 28, 275201) and give the website URL.

ELATE is open source software. Any queries or comments are welcome at

Summary of the properties

Input: stiffness matrix (coefficients in GPa) of NbBr5 (Materials Project id mp-568245)

         1       -1        1       -1       -1        1  
        -1        1        1        0       -0        0  
         1        1        2       -1       -0        0  
        -1        0       -1        1        0        0  
        -1       -0       -0        0        1       -0  
         1        0        0        0       -0       -1  

Average properties

Averaging schemeBulk modulusYoung's modulusShear modulusPoisson's ratio
VoigtKV = 0.66667 GPaEV = 1 GPaGV = 0.4 GPaνV = 0.25
ReussKR = 1 GPaER = 2.1429 GPaGR = 0.9375 GPaνR = 0.14286
HillKH = 0.83333 GPaEH = 1.5828 GPaGH = 0.66875 GPaνH = 0.18343

Eigenvalues of the stiffness matrix

λ1 λ2 λ3 λ4 λ5 λ6
-1.7515 GPa-0.41421 GPa0.15892 GPa 1 GPa 2.4142 GPa 3.5926 GPa
Stiffness matrix is not definite positive, crystal is mechanically unstable
No further analysis will be performed.