YSe2 crystallizes in the tetragonal P4/nmm space group. Y(1) is bonded in a 9-coordinate geometry to four equivalent Se(1) and five equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 8-coordinate geometry to four equivalent Y(1) and four equivalent Se(1) atoms. In the second Se site, Se(2) is bonded to five equivalent Y(1) atoms to form a mixture of distorted edge and corner-sharing SeY5 trigonal bipyramids.
YSe2 crystallizes in the tetragonal P4/nmm space group. Y(1) is bonded in a 9-coordinate geometry to four equivalent Se(1) and five equivalent Se(2) atoms. All Y(1)-Se(1) bond lengths are 3.05 Å. There is one shorter (2.97 Å) and four longer (2.99 Å) Y(1)-Se(2) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 8-coordinate geometry to four equivalent Y(1) and four equivalent Se(1) atoms. All Se(1)-Se(1) bond lengths are 2.88 Å. In the second Se site, Se(2) is bonded to five equivalent Y(1) atoms to form a mixture of distorted edge and corner-sharing SeY5 trigonal bipyramids.