Ba3UMnSe6 crystallizes in the trigonal R-3c space group. Ba(1) is bonded in a 8-coordinate geometry to eight equivalent Se(1) atoms. U(1) is bonded to six equivalent Se(1) atoms to form distorted USe6 pentagonal pyramids that share faces with two equivalent Mn(1)Se6 octahedra. Mn(1) is bonded to six equivalent Se(1) atoms to form MnSe6 octahedra that share faces with two equivalent U(1)Se6 pentagonal pyramids. Se(1) is bonded to four equivalent Ba(1), one U(1), and one Mn(1) atom to form a mixture of distorted face, corner, and edge-sharing SeBa4UMn octahedra. The corner-sharing octahedral tilt angles range from 0-67°.
Ba3UMnSe6 crystallizes in the trigonal R-3c space group. Ba(1) is bonded in a 8-coordinate geometry to eight equivalent Se(1) atoms. There are a spread of Ba(1)-Se(1) bond distances ranging from 3.33-3.46 Å. U(1) is bonded to six equivalent Se(1) atoms to form distorted USe6 pentagonal pyramids that share faces with two equivalent Mn(1)Se6 octahedra. All U(1)-Se(1) bond lengths are 2.85 Å. Mn(1) is bonded to six equivalent Se(1) atoms to form MnSe6 octahedra that share faces with two equivalent U(1)Se6 pentagonal pyramids. All Mn(1)-Se(1) bond lengths are 2.73 Å. Se(1) is bonded to four equivalent Ba(1), one U(1), and one Mn(1) atom to form a mixture of distorted face, corner, and edge-sharing SeBa4UMn octahedra. The corner-sharing octahedral tilt angles range from 0-67°.