code: public static boolean isTrigonalBipyramidal(IAtom atomA, IAtom atomB, IAtom atomC, IAtom atomD, IAtom atomE,
              IAtom atomF) {
          Point3d pointA = atomA.getPoint3d();
          Point3d pointB = atomB.getPoint3d();
          Point3d pointC = atomC.getPoint3d();
          Point3d pointD = atomD.getPoint3d();
          Point3d pointE = atomE.getPoint3d();
          Point3d pointF = atomF.getPoint3d();
  
          boolean isColinearABF = StereoTool.isColinear(pointA, pointB, pointF);
          if (isColinearABF) {
              // the normal to the equatorial plane
              Vector3d normal = StereoTool.getNormal(pointC, pointD, pointE);
  
              // get the side of the plane that axis point A is
              TetrahedralSign handednessCDEA = StereoTool.getHandedness(normal, pointC, pointF);
  
              // get the side of the plane that axis point F is
              TetrahedralSign handednessCDEF = StereoTool.getHandedness(normal, pointC, pointA);
  
              // in other words, the two axial points (A,F) are on opposite sides
              // of the equatorial plane CDE
              return handednessCDEA != handednessCDEF;
          } else {
              return false;
          }
      }
docs: Checks these 6 atoms to see if they form a trigonal-bipyramidal shape.
  
  @param atomA one of the axial atoms
  @param atomB the central atom
  @param atomC one of the equatorial atoms
  @param atomD one of the equatorial atoms
  @param atomE one of the equatorial atoms
  @param atomF the other axial atom
  @return true if the geometry is trigonal-bipyramidal