text: Some polysilicates are ladder polymers.  One example is provided by the mineral tremolite.
  In the area of coordination chemistry, the ladder structure is seen in some coordination polymers.  Illustrative is the polymer [CuI(2-picoline].  When the 2-picoline is replaced by a tertiary phosphine, it forms a tetrameric cubane-type cluster, [CuI(PR.  In both cases, the Cu(I) centers adopt tetrahedral molecular geometry.