text: The chair conformation is the most stable conformer.  At , 99.99% of all molecules in a cyclohexane solution adopt this conformation.
  The symmetry group is D. All carbon centers are equivalent. Six hydrogen centers are poised in axial positions, roughly parallel with the C3 axis, and six hydrogen atoms are parallel with the equator of the molecule.
  Each carbon bears one "up" and one "down" hydrogen. The C–H bonds in successive carbons are thus staggered so that there is little torsional strain. The chair geometry is often preserved when the hydrogen atoms are replaced by halogens or other simple groups. However, when these hydrogens are substituted for a larger group, strain is imposed upon the molecule due to diaxial interactions. This is an interaction (that is usually repulsive) between two substituents in the axial position on a cyclohexane ring.
  If one thinks of a carbon atom as a point with four half-bonds sticking out towards the vertices of a tetrahedron, they can imagine them standing on a surface with one half-bond pointing straight up. Looking from right above, the other three would appear to go outwards towards the vertices of an equilateral triangle, so the bonds would appear to have an angle of 120° between them. Now consider six such atoms standing on the surface so that their non-vertical half-bonds meet up and form a perfect hexagon. If three of the atoms are then reflected to be below the surface, the result will be something very similar to chair-conformation cyclohexane. In this model, the six vertical half-bonds are exactly vertical, and the ends of the six non-vertical half-bonds that stick out from the ring are exactly on the equator (that is, on the surface). Since C–H bonds are actually longer than half a C–C bond, the "equatorial" hydrogen atoms of chair cyclohexane will actually be below the equator when attached to a carbon that is above the equator, and vice versa. This is also true of other substituents. The dihedral angle for a series of four carbon atoms going around the ring in this model alternates between exactly +60° and −60° (called gauche).
  The chair conformation cannot deform without changing the bond angles or lengths. We can think of it as two chains, mirror images one of the other, containing atoms (1,2,3,4) and (1,6,5,4), with opposite dihedral angles. The distance from atom 1 to atom 4 depends on the absolute value of the dihedral angle. If these two dihedral angles change (still being opposite one of the other), it is not possible to maintain the correct bond angle at both carbon 1 and carbon 4.