Si3N4 crystallizes in the hexagonal P6_3/mmc space group. Si(1) is bonded to one N(2) and four equivalent N(1) atoms to form a mixture of corner and edge-sharing SiN5 trigonal bipyramids. There are two inequivalent N sites. In the first N site, N(1) is bonded in a see-saw-like geometry to four equivalent Si(1) atoms. In the second N site, N(2) is bonded in a trigonal planar geometry to three equivalent Si(1) atoms.
Si3N4 crystallizes in the hexagonal P6_3/mmc space group. Si(1) is bonded to one N(2) and four equivalent N(1) atoms to form a mixture of corner and edge-sharing SiN5 trigonal bipyramids. The Si(1)-N(2) bond length is 1.75 Å. There are two shorter (1.77 Å) and two longer (1.99 Å) Si(1)-N(1) bond lengths. There are two inequivalent N sites. In the first N site, N(1) is bonded in a see-saw-like geometry to four equivalent Si(1) atoms. In the second N site, N(2) is bonded in a trigonal planar geometry to three equivalent Si(1) atoms.