| A1 = C44/(C11 + C33 − 2C13) | A2 = 4C55/(C22 + C33 − 2C23) | A3 = 4C66/(C11 + C22 − 2C12) |
Graphene | −0.00087 | −0.00087 | 1 |
Silicene | 0.0024 | 0.002398 | 0.999999 |
Germanene | −0.1669 | −0.1669 | 1.000001 |
Stenane | −0.01893 | −0.01893 | 1.000002 |