YbB6 is Calcium hexaboride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Yb is bonded in a 1-coordinate geometry to twenty-four equivalent B atoms. All Yb–B bond lengths are 3.04 Å. B is bonded in a 1-coordinate geometry to four equivalent Yb and five equivalent B atoms. There is one shorter (1.66 Å) and four longer (1.74 Å) B–B bond length.