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17.31 c and d confusion

Posted: Sun Nov 26, 2017 11:39 pm
by Mike Matthews 1D
I'm a little bit confused because the book says that water as a ligand is denoted OH2 but in the solution for 17.31c the formula for tetraamminediaquacobalt(III) bromide is written as [Co(NH3)4(H20)2]Br3. Does anyone know why water is written as H2O here? I'm also confused because the book tells us to write the ligands in alphabetical order but in 17.31d, the formula for sodium bisoxalato(diaqua)ferrate(III) is written as Na[Fe(OH2)2(C2O4)2]. Alphabetically shouldn't (C2O4) be in front of the (OH2)?

Re: 17.31 c and d confusion

Posted: Mon Nov 27, 2017 6:17 am
by Chem_Mod
Hi Mike,

How water is written does not matter, so long as it is correctly written with two hydrogens and one oxygen. H2O and OH2 are equally correct.

For part d., because oxalate has the prefix bis-, this has higher priority than "diaqua" as b precedes d.

Hope this helps.

Re: 17.31 c and d confusion

Posted: Mon Nov 27, 2017 9:40 am
by AtreyiMitra2L
Chem_Mod wrote:Hi Mike,

How water is written does not matter, so long as it is correctly written with two hydrogens and one oxygen. H2O and OH2 are equally correct.

For part d., because oxalate has the prefix bis-, this has higher priority than "diaqua" as b precedes d.

Hope this helps.


But I thought that when we are writing everything alphabetically we aren't comparing the prefixes? Is this a special exception with greek prefixes? Also while the book asks us to write it in alphabetical order, when I asked you in class whether we had to do this you said that we can put the ligands in any order. Which Is correct?

Re: 17.31 c and d confusion

Posted: Thu Nov 30, 2017 1:35 pm
by alyssawhite1L
The ligands should be in alpabetical order according to their names, ignoring the prefixes (bi, tri, tetra, etc.). HOWEVER, when you use the other prefixes, (Bis, tris, tetris, etc) you order those (and only those) in alphabetical order according to all the prefixes.

Re: 17.31 c and d confusion

Posted: Thu Nov 30, 2017 5:00 pm
by Clarisse Wikstrom 1H
AtreyiMitra1E wrote:
Chem_Mod wrote:Hi Mike,

How water is written does not matter, so long as it is correctly written with two hydrogens and one oxygen. H2O and OH2 are equally correct.

For part d., because oxalate has the prefix bis-, this has higher priority than "diaqua" as b precedes d.

Hope this helps.


But I thought that when we are writing everything alphabetically we aren't comparing the prefixes? Is this a special exception with greek prefixes? Also while the book asks us to write it in alphabetical order, when I asked you in class whether we had to do this you said that we can put the ligands in any order. Which Is correct?


Just to clarify, H20 and OH2 are technically not the same when you write them. H20 denotes that thy Hydrogen is bonded to the transition metal, whereas OH2 denotes that the Oxygen is bonded to the transition metal, which is correct. The textbook be slippin sometimes so they probably just messed up, but Dr. Lavelle did briefly mention this difference in class when he was drawing out the lewis structures for coordination compounds.

Re: 17.31 c and d confusion

Posted: Thu Nov 30, 2017 5:05 pm
by Clarisse Wikstrom 1H
I forgot to mention that OH2 would be correct IF the transition metal was written on the LEFT side of water... if it was written on the RIGHT, it should be H2O :)