Elastic properties of transition metal dioxides: XO$_{2}$(X=Ru, Rh, Os,   Ir)
  The elastic properties of rutile transition metal dioxides XO$_{2}$ (X=Ru, Rh, Os, and Ir) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO$_2$ and IrO$_2$ show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides. 
Yanling Li, Zhi Zeng