Materials Data on Si3N4 by Materials Project

Si3N4 is Hausmannite structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six equivalent N3- atoms to form SiN6 octahedra that share corners with six equivalent SiN4 tetrahedra and edges with six equivalent SiN6 octahedra. All Si–N bond lengths are 1.89 Å. In the second Si4+ site, Si4+ is bonded to four equivalent N3- atoms to form corner-sharing SiN4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. All Si–N bond lengths are 1.79 Å. N3- is bonded in a distorted rectangular see-saw-like geometry to four Si4+ atoms.

氮化硅（Si₃N₄）具有黑锰矿（Hausmannite）型晶体结构，结晶于立方晶系Fd-3m空间群，其结构为三维网状。体系中存在两种不等价的四价硅（Si⁴⁺）位点：在第一种Si⁴⁺位点中，Si⁴⁺与六个等价的三价氮（N³⁻）原子配位，形成SiN₆八面体；该八面体与六个等价的SiN₄四面体共享顶角，同时与六个等价的SiN₆八面体共享边，所有Si–N键长均为1.89埃。在第二种Si⁴⁺位点中，Si⁴⁺与四个等价的N³⁻原子配位，形成共角连接的SiN₄四面体，共角八面体的倾斜角为57°，所有Si–N键长均为1.79埃。N³⁻原子以畸变的类矩形跷跷板配位几何与四个Si⁴⁺原子成键。