Li27As10 crystallizes in the monoclinic C2/m space group. There are ten inequivalent Li sites. In the first Li site, Li(1) is bonded to one Li(6), two equivalent Li(2), one As(2), and three equivalent As(1) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(1)Li3As4 tetrahedra,  a cornercorner with one Li(4)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(7)Li3As4 tetrahedra, corners with four equivalent Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with three equivalent Li(4)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, faces with two equivalent Li(3)Li2As4 tetrahedra, and faces with two equivalent Li(1)Li3As4 tetrahedra. In the second Li site, Li(2) is bonded in a 14-coordinate geometry to two equivalent Li(3), two equivalent Li(4), four equivalent Li(1), two equivalent As(2), and four equivalent As(1) atoms. In the third Li site, Li(3) is bonded to one Li(2), one Li(9), one As(2), and three equivalent As(1) atoms to form distorted LiLi2As4 tetrahedra that share  a cornercorner with one Li(4)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(7)Li3As4 tetrahedra, corners with three equivalent Li(3)Li2As4 tetrahedra, corners with four equivalent Li(1)Li3As4 tetrahedra,  an edgeedge with one Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and faces with two equivalent Li(1)Li3As4 tetrahedra. In the fourth Li site, Li(4) is bonded to one Li(2), one Li(6), one Li(9), one As(1), one As(3), and two equivalent As(2) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(3)Li2As4 tetrahedra,  a cornercorner with one Li(1)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with three equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(7)Li3As4 tetrahedra, edges with three equivalent Li(1)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(1)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and  a faceface with one Li(8)Li3As4 tetrahedra. In the fifth Li site, Li(5) is bonded to one Li(10), two equivalent Li(6), two equivalent As(2), and two equivalent As(3) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(5)Li3As4 tetrahedra, corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with two equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(8)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with four equivalent Li(7)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(8)Li3As4 tetrahedra, faces with two equivalent Li(4)Li3As4 tetrahedra, and faces with two equivalent Li(7)Li3As4 tetrahedra. In the sixth Li site, Li(6) is bonded in a 14-coordinate geometry to two equivalent Li(1), two equivalent Li(4), two equivalent Li(5), two equivalent Li(7), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. In the seventh Li site, Li(7) is bonded to one Li(10), one Li(6), one Li(9), one As(1), one As(3), and two equivalent As(2) atoms to form distorted LiLi3As4 tetrahedra that share corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with three equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(1)Li3As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with two equivalent Li(5)Li3As4 tetrahedra, edges with two equivalent Li(8)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(1)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and  a faceface with one Li(8)Li3As4 tetrahedra. In the eighth Li site, Li(8) is bonded to one Li(10), two equivalent Li(9), two equivalent As(2), and two equivalent As(3) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with two equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with four equivalent Li(7)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(8)Li3As4 tetrahedra, faces with two equivalent Li(4)Li3As4 tetrahedra, and faces with two equivalent Li(7)Li3As4 tetrahedra. In the ninth Li site, Li(9) is bonded in a 14-coordinate geometry to two equivalent Li(3), two equivalent Li(4), two equivalent Li(7), two equivalent Li(8), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. In the tenth Li site, Li(10) is bonded in a 14-coordinate geometry to two equivalent Li(5), two equivalent Li(8), four equivalent Li(7), two equivalent As(3), and four equivalent As(2) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 12-coordinate geometry to one Li(4), one Li(6), one Li(7), one Li(9), two equivalent Li(2), three equivalent Li(1), and three equivalent Li(3) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Li(1), one Li(10), one Li(2), one Li(3), one Li(5), one Li(6), one Li(8), one Li(9), two equivalent Li(4), and two equivalent Li(7) atoms. In the third As site, As(3) is bonded in a 13-coordinate geometry to one Li(10), two equivalent Li(4), two equivalent Li(5), two equivalent Li(6), two equivalent Li(7), two equivalent Li(8), and two equivalent Li(9) atoms.
Li27As10 crystallizes in the monoclinic C2/m space group. There are ten inequivalent Li sites. In the first Li site, Li(1) is bonded to one Li(6), two equivalent Li(2), one As(2), and three equivalent As(1) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(1)Li3As4 tetrahedra,  a cornercorner with one Li(4)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(7)Li3As4 tetrahedra, corners with four equivalent Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with three equivalent Li(4)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, faces with two equivalent Li(3)Li2As4 tetrahedra, and faces with two equivalent Li(1)Li3As4 tetrahedra. The Li(1)-Li(6) bond length is 2.71 Å. There is one shorter (2.71 Å) and one longer (2.72 Å) Li(1)-Li(2) bond length. The Li(1)-As(2) bond length is 2.62 Å. There are a spread of Li(1)-As(1) bond distances ranging from 2.56-2.72 Å. In the second Li site, Li(2) is bonded in a 14-coordinate geometry to two equivalent Li(3), two equivalent Li(4), four equivalent Li(1), two equivalent As(2), and four equivalent As(1) atoms. Both Li(2)-Li(3) bond lengths are 2.74 Å. Both Li(2)-Li(4) bond lengths are 2.76 Å. Both Li(2)-As(2) bond lengths are 3.03 Å. There are two shorter (2.89 Å) and two longer (3.10 Å) Li(2)-As(1) bond lengths. In the third Li site, Li(3) is bonded to one Li(2), one Li(9), one As(2), and three equivalent As(1) atoms to form distorted LiLi2As4 tetrahedra that share  a cornercorner with one Li(4)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(7)Li3As4 tetrahedra, corners with three equivalent Li(3)Li2As4 tetrahedra, corners with four equivalent Li(1)Li3As4 tetrahedra,  an edgeedge with one Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and faces with two equivalent Li(1)Li3As4 tetrahedra. The Li(3)-Li(9) bond length is 2.76 Å. The Li(3)-As(2) bond length is 2.72 Å. There are two shorter (2.69 Å) and one longer (2.70 Å) Li(3)-As(1) bond length. In the fourth Li site, Li(4) is bonded to one Li(2), one Li(6), one Li(9), one As(1), one As(3), and two equivalent As(2) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(3)Li2As4 tetrahedra,  a cornercorner with one Li(1)Li3As4 tetrahedra,  a cornercorner with one Li(5)Li3As4 tetrahedra,  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with three equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(7)Li3As4 tetrahedra, edges with three equivalent Li(1)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(1)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and  a faceface with one Li(8)Li3As4 tetrahedra. The Li(4)-Li(6) bond length is 2.68 Å. The Li(4)-Li(9) bond length is 2.71 Å. The Li(4)-As(1) bond length is 2.71 Å. The Li(4)-As(3) bond length is 2.64 Å. There is one shorter (2.59 Å) and one longer (2.61 Å) Li(4)-As(2) bond length. In the fifth Li site, Li(5) is bonded to one Li(10), two equivalent Li(6), two equivalent As(2), and two equivalent As(3) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(5)Li3As4 tetrahedra, corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with two equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(8)Li3As4 tetrahedra,  an edgeedge with one Li(8)Li3As4 tetrahedra, edges with two equivalent Li(1)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with four equivalent Li(7)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(8)Li3As4 tetrahedra, faces with two equivalent Li(4)Li3As4 tetrahedra, and faces with two equivalent Li(7)Li3As4 tetrahedra. The Li(5)-Li(10) bond length is 2.71 Å. Both Li(5)-Li(6) bond lengths are 2.72 Å. Both Li(5)-As(2) bond lengths are 2.64 Å. There is one shorter (2.68 Å) and one longer (2.71 Å) Li(5)-As(3) bond length. In the sixth Li site, Li(6) is bonded in a 14-coordinate geometry to two equivalent Li(1), two equivalent Li(4), two equivalent Li(5), two equivalent Li(7), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. Both Li(6)-Li(7) bond lengths are 2.71 Å. Both Li(6)-As(1) bond lengths are 2.95 Å. Both Li(6)-As(2) bond lengths are 3.07 Å. Both Li(6)-As(3) bond lengths are 3.09 Å. In the seventh Li site, Li(7) is bonded to one Li(10), one Li(6), one Li(9), one As(1), one As(3), and two equivalent As(2) atoms to form distorted LiLi3As4 tetrahedra that share corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with three equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(7)Li3As4 tetrahedra,  an edgeedge with one Li(3)Li2As4 tetrahedra,  an edgeedge with one Li(1)Li3As4 tetrahedra,  an edgeedge with one Li(7)Li3As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with two equivalent Li(5)Li3As4 tetrahedra, edges with two equivalent Li(8)Li3As4 tetrahedra,  a faceface with one Li(3)Li2As4 tetrahedra,  a faceface with one Li(1)Li3As4 tetrahedra,  a faceface with one Li(4)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(7)Li3As4 tetrahedra, and  a faceface with one Li(8)Li3As4 tetrahedra. The Li(7)-Li(10) bond length is 2.70 Å. The Li(7)-Li(9) bond length is 2.71 Å. The Li(7)-As(1) bond length is 2.63 Å. The Li(7)-As(3) bond length is 2.72 Å. There is one shorter (2.57 Å) and one longer (2.62 Å) Li(7)-As(2) bond length. In the eighth Li site, Li(8) is bonded to one Li(10), two equivalent Li(9), two equivalent As(2), and two equivalent As(3) atoms to form distorted LiLi3As4 tetrahedra that share  a cornercorner with one Li(8)Li3As4 tetrahedra, corners with two equivalent Li(3)Li2As4 tetrahedra, corners with two equivalent Li(1)Li3As4 tetrahedra, corners with two equivalent Li(4)Li3As4 tetrahedra, corners with three equivalent Li(5)Li3As4 tetrahedra,  an edgeedge with one Li(5)Li3As4 tetrahedra, edges with two equivalent Li(3)Li2As4 tetrahedra, edges with two equivalent Li(4)Li3As4 tetrahedra, edges with four equivalent Li(7)Li3As4 tetrahedra,  a faceface with one Li(5)Li3As4 tetrahedra,  a faceface with one Li(8)Li3As4 tetrahedra, faces with two equivalent Li(4)Li3As4 tetrahedra, and faces with two equivalent Li(7)Li3As4 tetrahedra. The Li(8)-Li(10) bond length is 2.73 Å. Both Li(8)-Li(9) bond lengths are 2.69 Å. Both Li(8)-As(2) bond lengths are 2.59 Å. There is one shorter (2.67 Å) and one longer (2.74 Å) Li(8)-As(3) bond length. In the ninth Li site, Li(9) is bonded in a 14-coordinate geometry to two equivalent Li(3), two equivalent Li(4), two equivalent Li(7), two equivalent Li(8), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. Both Li(9)-As(1) bond lengths are 3.05 Å. Both Li(9)-As(2) bond lengths are 2.98 Å. Both Li(9)-As(3) bond lengths are 3.07 Å. In the tenth Li site, Li(10) is bonded in a 14-coordinate geometry to two equivalent Li(5), two equivalent Li(8), four equivalent Li(7), two equivalent As(3), and four equivalent As(2) atoms. Both Li(10)-As(3) bond lengths are 2.86 Å. All Li(10)-As(2) bond lengths are 3.08 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 12-coordinate geometry to one Li(4), one Li(6), one Li(7), one Li(9), two equivalent Li(2), three equivalent Li(1), and three equivalent Li(3) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to one Li(1), one Li(10), one Li(2), one Li(3), one Li(5), one Li(6), one Li(8), one Li(9), two equivalent Li(4), and two equivalent Li(7) atoms. In the third As site, As(3) is bonded in a 13-coordinate geometry to one Li(10), two equivalent Li(4), two equivalent Li(5), two equivalent Li(6), two equivalent Li(7), two equivalent Li(8), and two equivalent Li(9) atoms.