Huckel model with ones-electron per atom is used to study the geometries and electronic structures of clusters of 9 to 22 atoms. Two different optimization schemes for obtaining the ground states are used; (i) minimization of an approximate Huckel ground state energy starting from a random geometry and (ii) simulated annealing. Both methods give similar and new ground state geometries for clusters with 10 to 14 atoms. All clusters with more than 10 atoms will be distorted if the bond distance is allowed to vary +/-5.5%. The ground states of clusters with atoms 10, 11, 12, and 14 are found to have the N=9 cluster as the basic building block, whereas the N=13 cluster is a distorted cuboctahedron. As a general trend, the deformation of clusters increases from atom number 8 to 14 and shrinks again from 15 to 20 atoms, in accordance with jellium model results.