Molecular structure of the nineteen-vertex selenaborane SeB18H20(4) drawn with 50 % probability ellipsoids for non-hydrogen atoms. Interatomic distances (A) to Se(9): B(4) 2.138(4), B(5) 2.115(4), B(8) 2.183(4), B(10) 2.118(4). B(7)-B(8) 1.824(6), B(7)-B(11) 1.929(5), B(10)-B(11) 1.836(6), B(7)-B(10') 2.087(6), B(7')-B(8) 1.932(6), B(7')-B(10') 2.087(6). Angles (): B(8)-Se(9)-B(10) 92.4(1), Se(9)-B(10)-B(11) 115.1(2), B(10)-B(11)-B(7) 109.4(2), Se(9)-B(8)-B(7) 114.6(2), B(11)-B(7)-B(8) 108.1(2). Table S9 lists further interatomic dimensions.
