Mn3As2 crystallizes in the orthorhombic Cmc2_1 space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one As(3), one As(4), two equivalent As(1), and two equivalent As(2) atoms to form MnAs6 octahedra that share corners with four equivalent Mn(3)As5 square pyramids, corners with four equivalent Mn(5)As5 square pyramids, corners with two equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(1)As6 octahedra, edges with three equivalent Mn(4)As5 trigonal bipyramids,  a faceface with one Mn(3)As5 square pyramid, and  a faceface with one Mn(5)As5 square pyramid. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one As(1), one As(2), one As(3), and two equivalent As(4) atoms. In the third Mn site, Mn(3) is bonded to one As(4), two equivalent As(2), and two equivalent As(3) atoms to form distorted MnAs5 square pyramids that share corners with four equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(3)As5 square pyramids, edges with two equivalent Mn(5)As5 square pyramids,  an edgeedge with one Mn(4)As5 trigonal bipyramid, and  a faceface with one Mn(1)As6 octahedra. The corner-sharing octahedral tilt angles range from 54-55°. In the fourth Mn site, Mn(4) is bonded to one As(2), two equivalent As(1), and two equivalent As(3) atoms to form distorted MnAs5 trigonal bipyramids that share corners with two equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(3)As5 square pyramids, corners with four equivalent Mn(5)As5 square pyramids, edges with three equivalent Mn(1)As6 octahedra,  an edgeedge with one Mn(3)As5 square pyramid,  an edgeedge with one Mn(5)As5 square pyramid, and edges with two equivalent Mn(4)As5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 19°. In the fifth Mn site, Mn(5) is bonded to one As(3), two equivalent As(1), and two equivalent As(4) atoms to form distorted MnAs5 square pyramids that share corners with four equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(3)As5 square pyramids, edges with two equivalent Mn(5)As5 square pyramids,  an edgeedge with one Mn(4)As5 trigonal bipyramid, and  a faceface with one Mn(1)As6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. In the sixth Mn site, Mn(6) is bonded in a 4-coordinate geometry to one As(1), one As(4), and two equivalent As(2) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to one Mn(2), one Mn(6), two equivalent Mn(1), two equivalent Mn(4), and two equivalent Mn(5) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Mn(2), one Mn(4), two equivalent Mn(1), two equivalent Mn(3), and two equivalent Mn(6) atoms. In the third As site, As(3) is bonded to one Mn(1), one Mn(2), one Mn(5), two equivalent Mn(3), and two equivalent Mn(4) atoms to form distorted edge-sharing AsMn7 pentagonal bipyramids. In the fourth As site, As(4) is bonded in a 7-coordinate geometry to one Mn(1), one Mn(3), one Mn(6), two equivalent Mn(2), and two equivalent Mn(5) atoms.
Mn3As2 crystallizes in the orthorhombic Cmc2_1 space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one As(3), one As(4), two equivalent As(1), and two equivalent As(2) atoms to form MnAs6 octahedra that share corners with four equivalent Mn(3)As5 square pyramids, corners with four equivalent Mn(5)As5 square pyramids, corners with two equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(1)As6 octahedra, edges with three equivalent Mn(4)As5 trigonal bipyramids,  a faceface with one Mn(3)As5 square pyramid, and  a faceface with one Mn(5)As5 square pyramid. The Mn(1)-As(3) bond length is 2.48 Å. The Mn(1)-As(4) bond length is 2.51 Å. Both Mn(1)-As(1) bond lengths are 2.59 Å. Both Mn(1)-As(2) bond lengths are 2.55 Å. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one As(1), one As(2), one As(3), and two equivalent As(4) atoms. The Mn(2)-As(1) bond length is 2.65 Å. The Mn(2)-As(2) bond length is 2.67 Å. The Mn(2)-As(3) bond length is 2.52 Å. Both Mn(2)-As(4) bond lengths are 2.53 Å. In the third Mn site, Mn(3) is bonded to one As(4), two equivalent As(2), and two equivalent As(3) atoms to form distorted MnAs5 square pyramids that share corners with four equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(3)As5 square pyramids, edges with two equivalent Mn(5)As5 square pyramids,  an edgeedge with one Mn(4)As5 trigonal bipyramid, and  a faceface with one Mn(1)As6 octahedra. The corner-sharing octahedral tilt angles range from 54-55°. The Mn(3)-As(4) bond length is 2.42 Å. Both Mn(3)-As(2) bond lengths are 2.46 Å. Both Mn(3)-As(3) bond lengths are 2.44 Å. In the fourth Mn site, Mn(4) is bonded to one As(2), two equivalent As(1), and two equivalent As(3) atoms to form distorted MnAs5 trigonal bipyramids that share corners with two equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(3)As5 square pyramids, corners with four equivalent Mn(5)As5 square pyramids, edges with three equivalent Mn(1)As6 octahedra,  an edgeedge with one Mn(3)As5 square pyramid,  an edgeedge with one Mn(5)As5 square pyramid, and edges with two equivalent Mn(4)As5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 19°. The Mn(4)-As(2) bond length is 2.49 Å. Both Mn(4)-As(1) bond lengths are 2.56 Å. Both Mn(4)-As(3) bond lengths are 2.48 Å. In the fifth Mn site, Mn(5) is bonded to one As(3), two equivalent As(1), and two equivalent As(4) atoms to form distorted MnAs5 square pyramids that share corners with four equivalent Mn(1)As6 octahedra, corners with four equivalent Mn(4)As5 trigonal bipyramids, edges with two equivalent Mn(3)As5 square pyramids, edges with two equivalent Mn(5)As5 square pyramids,  an edgeedge with one Mn(4)As5 trigonal bipyramid, and  a faceface with one Mn(1)As6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. The Mn(5)-As(3) bond length is 2.38 Å. Both Mn(5)-As(1) bond lengths are 2.55 Å. Both Mn(5)-As(4) bond lengths are 2.50 Å. In the sixth Mn site, Mn(6) is bonded in a 4-coordinate geometry to one As(1), one As(4), and two equivalent As(2) atoms. The Mn(6)-As(1) bond length is 2.47 Å. The Mn(6)-As(4) bond length is 2.40 Å. Both Mn(6)-As(2) bond lengths are 2.39 Å. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to one Mn(2), one Mn(6), two equivalent Mn(1), two equivalent Mn(4), and two equivalent Mn(5) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Mn(2), one Mn(4), two equivalent Mn(1), two equivalent Mn(3), and two equivalent Mn(6) atoms. In the third As site, As(3) is bonded to one Mn(1), one Mn(2), one Mn(5), two equivalent Mn(3), and two equivalent Mn(4) atoms to form distorted edge-sharing AsMn7 pentagonal bipyramids. In the fourth As site, As(4) is bonded in a 7-coordinate geometry to one Mn(1), one Mn(3), one Mn(6), two equivalent Mn(2), and two equivalent Mn(5) atoms.