A puckered conformation in which carbons 1 and 4 are
 bent toward each other
 •a boat conformation is less
 stable than a chair conformation by 6.5 kcal (27 kJ)/mol
 •torsional strain is created
 by four sets of eclipsed hydrogen interactions
 •steric strain (nonbonded interaction strain)
 is created by one set of flagpole interactions