MYTUTOR SUBJECT ANSWERS

531 views

Why are transition metal complexes coloured?

By definition, all transition metal ions have d orbitals. These are normally degenerate, lying at the same energy level as there is nothing to break the symmetry.

However, in the presence of ligands, the symmetry is broken and the orbitals split into different energy levels. This is due to differing alignment with the ligands resulting in a different electric repulsion from then lone pairs on the ligands.

For example, in an octohedral complex like [Cu(H2O)6]2+, the dx2-y2 and dz2 orbitals point directly at the ligands whereas the dxy, dxz and dyz orbitals all lie between the ligands. This means that the former experience greater electronic repulsion and are therefore raised in energy compared to the latter.

The split in energy levels means that electrons can be excited from the lower to the higher energy level by absorbing a photon. The energy of the this photon relates to its frequency by E=hf meaning that complexes absorb light of one partiular colour. They therefore transmit the complimentary colour and this happens to be in the visible light range so they appear coloured.

Zac T. A Level Chemistry tutor, A Level Further Mathematics  tutor, A...

12 months ago

Answered by Zac, an A Level Chemistry tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

125 SUBJECT SPECIALISTS

£22 /hr

Jay G.

Degree: Biological Sciences (Biochemistry) (Bachelors) - Edinburgh University

Subjects offered:Chemistry, Maths+ 2 more

Chemistry
Maths
Mandarin
Biology

“I am here not only to help you get better at exams, but to help you enjoy your subject more ”

£20 /hr

Darragh C.

Degree: Biomedical Sciences (Neuroscience) (Bachelors) - Edinburgh University

Subjects offered:Chemistry, Biology+ 1 more

Chemistry
Biology
-Personal Statements-

“About me:I study neuroscience at Edinburgh University, and have previously studied Chemistry at University College Dublin. Understanding more about the world around me has always been something I'm passionate about, and science has ...”

MyTutor guarantee

£22 /hr

Emma R.

Degree: Chemistry (Masters) - Durham University

Subjects offered:Chemistry, Maths+ 1 more

Chemistry
Maths
Biology

“I find tutoring both fun and incredibly rewarding and look forward to working with my students to fulfil their potential and achieve their target grades. ”

About the author

Zac T.

Currently unavailable: until 03/10/2016

Degree: Natural Sciences (Bachelors) - Cambridge University

Subjects offered:Chemistry, Science+ 4 more

Chemistry
Science
Physics
Maths
Further Mathematics
Biology

“About me I am a student at the University of Cambridge where I study Natural Sciences, a course which allows me to maintain my interest in multiple areas of science and maths. I take modules in Chemistry, Physics, Earth Science and Ma...”

MyTutor guarantee

You may also like...

Posts by Zac

Find the shortest distance between the line L: x=1+t, y=1+2t, z=1-t and the point A: (2,3,4)

How can the average speedx of a gas molecule be derived?

Integrate (x+4)/(x^2+2x+2)

Why are transition metal complexes coloured?

Other A Level Chemistry questions

Why are transition metal complexes coloured?

What is an isotope?

A bromoalkane contains 34.9% carbon and 6.60% hydrogen by mass. The rest of the mass is made up by bromine. What is the empirical formula of this molecule?

Describe two different test tube reactions to identify the following organic compounds: propanal and benzoic acid.

View A Level Chemistry tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok