The electron group geometry of ASH3 is tetrahedral, while its molecular geometry is trigonal pyramidal.
In ASH3, arsenic (As) is the central atom bonded to three hydrogen (H) atoms. The presence of a lone pair on the arsenic atom affects the molecular shape. The tetrahedral electron group geometry results from four regions of electron density (three bonding pairs with H and one lone pair). However, because of the lone pair, the actual shape that we observe is trigonal pyramidal. In summary, the hybridization is sp3, leading to the tetrahedral arrangement of electron groups, and the actual shape is trigonal pyramidal due to the influence of the lone pair on the geometry.