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 Si3W (Materials Project id mp-972748)

       -94      443      101        0        0        0  
       443      -94      101        0        0        0  
       101      101      216        0        0        0  
         0        0        0        8        0        0  
         0        0        0        0        8        0  
         0        0        0        0        0     -268  

Average properties

Averaging schemeBulk modulusYoung's modulusShear modulusPoisson's ratio
VoigtKV = 146.44 GPaEV = -346.87 GPaGV = -91.533 GPaνV = 0.89477
ReussKR = 145.84 GPaER = 55.565 GPaGR = 19.34 GPaνR = 0.4365
HillKH = 146.14 GPaEH = -118 GPaGH = -36.096 GPaνH = 0.63458

Eigenvalues of the stiffness matrix

λ1 λ2 λ3 λ4 λ5 λ6
-537 GPa -268 GPa 8 GPa 8 GPa 124.94 GPa 440.06 GPa
Stiffness matrix is not definite positive, crystal is mechanically unstable
No further analysis will be performed.