Coordination Compounds

Chemistry · Class 12

Simulation · Chemistry · Class 12

Build coordination isomers and turn them in 3D

"Build coordination isomers and turn them in 3D" is a free, interactive Class 12 Chemistry simulation for NEET and JEE, built on the NCERT section "Geometrical and optical isomerism" in Coordination Compounds. A rotatable 3D octahedron, square plane or tetrahedron: place ligands (A, B, or a bidentate AA), and the sim tests whether two builds are the same by rotation and whether a build is superimposable on its mirror image. NEET has asked about this idea 3 times in 10 years of papers. JEE Main asked 80 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).

From the lesson Geometrical and optical isomerism in Coordination Compounds. Change the values and watch what happens.

Build coordination isomers and turn them in 3DChemistry · Class 12

What it shows

NCERT §5.4.1; §5.4.2

A rotatable 3D octahedron, square plane or tetrahedron: place ligands (A, B, or a bidentate AA), and the sim tests whether two builds are the same by rotation and whether a build is superimposable on its mirror image.

Controls

4 to try

  • Togglegeometry octahedral / square planar / tetrahedral
  • Clickvertex to place A, B or one end of AA
  • Dragrotate the model
  • Buttonshow mirror image / overlay

Try this

Build fac- and mer-[MA₃B₃], then find which of cis- or trans-[MA₂(AA)₂] is chiral.

Common mistake

Tetrahedral [MA₂B₂] has cis and trans forms / trans-[M(AA)₂B₂] is optically active.

In NEET

10 years of papers

Asked 3 times in 10 years of NEET.

See the past questions: Coordination Isomerism, Coordination Compounds (chapter)

In JEE Main

42 shifts analysed

80 questions from Coordination Compounds across the 42 JEE Main shifts Lumi has analysed (2017–2026).

See the past questions

The idea behind it

NCERT §5.4.1; §5.4.2

  • Isomers share a formula but differ in how the atoms are arranged. Stereoisomers have the same bonds in different spatial arrangements; structural isomers have different bonds.
  • Geometrical isomerism appears in heteroleptic complexes of CN 4 and 6. In square planar [MX₂L₂], the two X ligands sit side by side (cis) or across from each other (trans), as in cis- and trans-[Pt(NH₃)₂Cl₂].
  • Square planar [MABXL] with four different unidentate ligands has three geometrical isomers: two cis and one trans.
  • Tetrahedral complexes never show geometrical isomerism: every position is adjacent to every other, so the ligands' relative positions are all alike.
  • Octahedral [MX₂L₄] ([Co(NH₃)₄Cl₂]⁺) and [MX₂(L–L)₂] ([CoCl₂(en)₂]⁺) also form cis and trans isomers.
  • Octahedral [Ma₃b₃], such as [Co(NH₃)₃(NO₂)₃], gives fac and mer isomers: three identical donors on the corners of one face (facial), or along a meridian of the octahedron (meridional).
  • Optical isomers (enantiomers) are non-superimposable mirror images, and such molecules or ions are chiral. The dextro (d) form rotates plane-polarised light to the right and the laevo (l) form to the left in a polarimeter.
  • Optical isomerism is common in octahedral complexes with didentate ligands, e.g. [Co(en)₃]³⁺. For [PtCl₂(en)₂]²⁺ only the cis isomer is optically active; the trans form has a mirror plane.
  • Of cis- and trans-[CrCl₂(ox)₂]³⁻, only the cis form is chiral.

Questions

5 answers

What does the "Build coordination isomers and turn them in 3D" simulation show?
A rotatable 3D octahedron, square plane or tetrahedron: place ligands (A, B, or a bidentate AA), and the sim tests whether two builds are the same by rotation and whether a build is superimposable on its mirror image.
What mistake does the "Build coordination isomers and turn them in 3D" simulation fix?
A common mistake it clears up: tetrahedral [MA₂B₂] has cis and trans forms / trans-[M(AA)₂B₂] is optically active.
Has NEET asked about this idea?
Yes. NEET has asked about this idea 3 times in 10 years of papers.
Does JEE Main ask questions from Coordination Compounds?
Yes. JEE Main asked 80 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
Is this simulation free?
Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Geometrical and optical isomerism" in Coordination Compounds (Class 12 Chemistry).

Embed this simulation

Free, with a link back

Teaching this idea? Put the simulation on your own page or LMS with this code.