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Molkit

Newman Projection

A Newman projection shows a carbon-carbon bond viewed end-on: three front bonds meet at a center point in a Y arrangement, and three back bonds emerge from behind a circle that represents the rear carbon. Molkit draws all six substituents as real atoms, so you can relabel them like any other atom, and it tracks the dihedral angle so you can rotate between staggered and eclipsed conformations.

Placing a Newman projection

Click the projection tool in the toolbar to open the projection flyout (press J to activate the tool from the keyboard), then pick from the Newman row. Right-clicking the tool button also opens the flyout.

Four variants are available:

  • Staggered: 60 degree dihedral, all positions labeled H
  • Eclipsed: 0 degree dihedral, all positions labeled H
  • Anti: 180 degree dihedral with a CH3 group on the front and back
  • Gauche: 60 degree dihedral with a CH3 group on the front and back

Click the canvas to place the projection. Molkit creates the atoms, selects them, and switches to the Select tool automatically.

Editing substituents

Double-click any substituent atom, front or back, to open its label editor and type a new group such as OH, Br, or CH2OH. The two center carbons are not labeled and cannot be edited this way.

Rotating the back carbon

Drag any back substituent to rotate the entire back set around the bond axis. The dihedral angle snaps to multiples of 60 degrees within a 5 degree tolerance; hold Shift to disable snapping. A live readout above the circle shows the current angle and conformation name.

When the conformation label is enabled, Molkit prints eclipsed, gauche, or anti below the projection whenever the dihedral falls in the matching range. Near-eclipsed back bonds are offset by a few degrees so they peek out from behind the front bonds; adjust this with the Eclipsed Offset slider.

Projection Properties panel

Selecting any atom of the projection opens the Projection Properties panel:

  • Dihedral: angle slider (0 to 360 degrees), preset buttons (Eclipsed, Gauche, Anti), an optional angle arc, and the conformation label with size, color, italic, and bold controls
  • Circle: radius, fill (none, white, or canvas background), and stroke thickness
  • Bonds: bond length and eclipsed offset
  • Appearance: line thickness, color, and an optional center dot on the front carbon

Double-click any slider to reset it to its default value.

Deleting

Select the projection’s atoms (a marquee drag is easiest) and press Delete. Deleting the front or back center carbon removes the whole projection; deleting a single substituent removes just that position.

See also