Tunnel-structured willemite Zn2SiO4: Electronic structure, elastic, and thermal properties

Abstract Willemite Zn 2 SiO 4 crystallizes in such a way that and Si are tetrahedrally coordinated with O an ionic-covalent manner to form ZnO tetrahedra as the building units. The corner-sharing, of which one SiO4 tetrahedron connects eight tetrahedra, links four tetrahedra. unique crystallographic configuration gives rise parallel tunnels diameter 5.7 Å along c -axis direction. tunnel structure definitely correlates its interesting elastic thermal properties. On hand, modulus, coefficient expansion (CTE), conductivity low. has low Vickers hardness 6.6 GPa at 10 N 2.34 W/(m·K) 1073 K. other modulus CTE significantly larger than those - b -axes, showing obvious anisotropy. Specifically, Young’s z direction ( E = 179 GPa) is almost twice x y directions 93 GPa). high anisotropy ascribed empty -axis, capable more accommodating -axes. striking properties hardness, CTE, make it much useful various fields ceramics, expansion, insulation, machining tools.