Why anhydrous copper sulphate is colourless

Sit and relax as our customer representative will contact you within 1 business day Continue. Forum Inorganic Chemistry cusoh2o-is-blue-in-colour-while-cuso4-is Enter email id Enter mobile number. Cancel Notify me. Srikanth Neeli 38 Points. Shakti Prateek 14 Points. Gaurav jhaa 9 Points. Since aq. CuSO4 contains 5H2O molecules which act as ligand and due to LMCT Ligand to Metal Charge Transfer the colour of sloution is blue, it is not due to d-d transition since it is d9 system so there is no any posiblity of d-d transition.

For more detail go through J. Huhyee or contact me -. Sagnik Mukherjee 11 Points. In the case of CuSO 4.

But in the case of CuSO 4 no d-d transition is observed so it is colourless. And these 5 water of hydration helps in LMCT to be it blue in colour.. For more contact …. Gaurav jhaa. Arsalaan 13 Points. Idimiyo Gift 13 Points. However, zink II in ZnSO4 has completely filled d-level [Ar] 4s0 3d10 with no possibility to move some electrons within that level. In turn, those transfers of the electrons within the d-level are making d-metal cations colored.

Sumeet 19 Points. Its a D block transition metal, with an empty D orbital, therefore forms coordination complexes easily resulting in the absorption of crystalisation of water. The unpaired electron movement in tthe d-d transition is responsible for the blue colour.

Saneha 15 Points. Although the question is a bit old, I think it still hasn't been answered yet. And by looking at the given answers it seems like the discussion went into a different direction at some point. Those two are similar in their ligand field splitting, where the latter one is slightly weaker, so we expect a red-shift of the absorption energy.

And that is also what Nagase et al. As shown partly in Fig. The observed spectral changes thus come about.

So, according to the Jahn Teller theorem , these octahedral shapes will undergo slight distortions and will not be a perfect octahedron. It is easy to see why it is so. While in the anhydrous form, we can clearly see that a centre of symmetry will be present, and so transitions will be Laporte-forbidden.

The reason behind this is the splitting effect. The energy difference i. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why is anhydrous copper II sulfate white while the pentahydrate is blue, even though both have one unpaired electron? Ask Question. Asked 4 years, 7 months ago.

Active 1 year, 5 months ago. Viewed 6k times. Improve this question. Kartik Kartik 3 3 gold badges 8 8 silver badges 21 21 bronze badges. Add a comment. Active Oldest Votes. Sone and Y. Fukuda Ref. References: K.