Naming Complex Ions & Coordination Compounds | Chemistry

[00:00:00]naming complex ions and coordination compounds going to be the topic of this lesson my name is chad and welcome to chad's prep where my goal is to take the stress out of learning science now in addition to high school and college science prep we also offer datm cat and oat prep as well i'll leave a link in the description below for where you can find those courses now this lesson is part of my new general chemistry playlist which is almost finished but for a couple more weeks i'll still be releasing several lessons a week throughout the school year and i'll be starting a new playlist shortly thereafter so if you want to be notified every time i post a new lesson or get started on my next playlist then subscribe to the channel click the bell notification all right so naming complex ions and coordination compounds and we're going to split this up into cations and anions and technically we're going to name both cations and neutral complexes in one way so especially when you name the metal part of it but with the anions we're going to do it slightly different for certain examples for certain metals as we'll see so we'll start with a complex cation here and so we try to make this as confusing as possible just so you know and in the formula we put the metal first in the ligand second but in the name we put the ligands first and the metal at the end of that complex ion so again just trying to make it confusing it's my guess so we're going to name the ligands first and it turns out you name the ligands you name them in alphabetical order based on how they're named so again water is not named as water it's named as aqua ammonia is not named as ammonia it's named as amine and then cl is chloro turns out and we'll name them in alphabetical order so in this case amine is going to come first am then aqua aq and then chloro c h after that so turns out you're also going to use a numerical prefix to tell you uh to tell me exactly how many there are so 2 is for die three for try four for tetra five for penta six for hexa if there's only one though you're just gonna use no prefix whatsoever you don't you don't say mono or anything like that you just leave the prefix off and so for this first one here so we gotta start off again naming the amine first we got three of them so we're going to say try amine if you've had organic chemistry you'll notice that a lot of nitrogen containing compounds are called amines with only one m so but here in coordination chemistry so as a ligand amine has two m's in it so just a word of the wise there so triamine we've got three amine ligands so and then aqua is next in the alphabet so we have two of those so it's going to be di aqua and then just the one chloro so we're just going to say chloro all right and then once you've named all those ligands you finally named the metal and in this case cr stands for chromium so we're just going to say chromium big long word and then in parentheses you're gonna put the oxidation state of that uh metal and you might have to figure it out based on what it's with here so you're gonna have to know the charges on your ligands unfortunately now i can see that this entire complex ion has an overall charge of plus two so but you're supposed to know that aqua and amine have no overall charge they're neutral and then chloro is minus one and so if there's just this one ligand that's minus one well then we can deduce that the chromium must be plus 3 if the overall complex ion is going to be plus 2. and so you've got to put the roman numeral 3 in parentheses there and so this is the triamine diaquachloro chromium 3 ion and so if you're only got just the cation just the animal you're going to say ion at the end it's kind of like if you had na plus what would you call this would you just call it sodium no you call it a sodium ion at the end of the name so if you've got just a cation or just an anion say ion at the end all right so for cations and neutral species this is kind of how it goes what we'll see is just going to be a difference is that when you name the metal for a complex anion you're always going to end it with an ate ending so had this overall had a negative charge for the entire complex well then we would have said chromate now notice i'm saying it's a negative charge for the entire complex the metal itself is always you know it's never going able to have a negative oxidation uh negative oxidation state it's either going to be positive or in certain rare cases it might be neutral but it's always going to be positive but the key is if the entire complex has an overall negative charge like it does here that's when you'd end it with an at ending we wouldn't have said chromium we would have said chromate so and to make this even trickier again uh it turns out that for select metals you're going to use the latin root with the ate ending as well so if you notice we get quite a few transition metals that the symbol does not correspond to the english name like iron fe why does match so an fe comes from the latin fair and so when you have a complex anion with iron you don't say ironate you say ferrate and so there's certain ones you should know and i've put them on the hand out here so we've got uh uh fe is uh ferry cu notice copper is co but cu is the symbol and that's cupra and so it'd be cuprate so ag argentate if you've spoken any french you'll you'll know that uh large ant is money or silver you know so uh then you've got a u would be orate for gold which we're gonna use here and then pb plum bait uh definitely lead doesn't uh uh begin with a pb right and then sn for stan so which is uh tin so we'd say stan eight and again this only applies to the complex anions so if i have a complex cation and gold's a part of it i'm just going to say gold if you know irons are part of it i'm just going to say iron so it's only for the complex anions that i use these latin roots with an ate ending all right so in this case uh we're gonna name the ligands first yet again so we got four chloro ligands and four is tetra so we're gonna say tetra chloro so and then instead of gold here because this has a negative charge had it had a positive charge of neutral we would have just said gold but again because it has an overall negative charge on this complex anion we'll use orate a-u-r-a-t-e and then again roman numeral in parentheses and chloro's minus one so gold must overall be plus four if the the entire complex ion has their own overall negative two charge and so we'll put the roman numeral four here so let's let's get that right not four how did i get that how about two plus two so plus two and minus four here for a total of minus two and so this is the tetrachlororate two ion okay so we got one other thing to uh to deal with here and that's when you got like polydentate ligands like we do here in this case and so you got to know their names unfortunately so name this thing so en is the short for ethylenediamine like ophen would be short for o phenanthraline and again these are on that big list of ligands that are part of the study guide here and so uh oxalato would just be an ox in parentheses and uh diethylene triamine would be a d-i-e-n in parentheses and things of a sort uh so you gotta know these names unfortunately because when you go to name them the entire name is part of the name where it's just some little abbreviations part of the formula so we're gonna name all of our polydentate ligands in this case first or just ligands and it's ethylenediamine and there's three of them well it turns out with polydentate ligands you don't use the ditri tetra you're going to use bis tris and tetrakis oddly enough and since there's three of them we're gonna say tris not try so you remember that that's for polydentate liggins a little bit different numerical prefixes so this is tris ethylenediamine and notice diamine here just has one m not two as part of this big word ethylenediamine oddly enough so and then we're gonna go to naming the metal and notice because we have a complex cation we're not gonna say ferrate here we're just going to say iron and then we've got to put a roman numeral in parentheses yet again and in this case you're supposed to know not only that ethylene is bident ethylene diamine is biodentate but also it's neutral it's no overall charge and so in this case the iron must be responsible for the entire plus two charge therefore the roman numeral two and we're dealing with just an ion not an entire compound here and so this is tris ethylenediamine iron two ion okay so now we're going to do a couple examples of entire coordination compounds where we have both cation and anion so and it's going to work like we named other ionic compounds you name the cation first you name the anion second so and if they're simple great and if they're complex well now we've learned some new rules for naming them as complex ions and stuff but we're gonna have be putting those together so if we got like you know an a plus that's the sodium ion if we got cl minus that's the chloride ion but if we got nacl that's now sodium chloride an entire ionic compound and that's kind of where we're headed with this with entire coordination compounds where we have both caron and anion and at least one of them is going to be complex in this chapter but in the last example we'll see where we have both the complex cation and a complex anion let's take a look so just a second ago we named this lovely complex catim and it was the triamine diaqua chlorochromium 3 ion since chromium was in the plus 3 oxidation state and now we're going to make this cation part of an entire ionic compound as well and so in this case we're going to get rid of that plus 2 charge and just put a couple of chloride counter ions here overall neutral ionic compound now and so when you name an ionic compound you're still going to start cation first and in second so we're going to name the cation first but since it's not just a cation by itself we'll take away that ion and so once you've said the entire cation then you're just going to name the anion in this case it's just a simple anion and we're just going to say chloride notice it's not dichloride or anything like that notice if we have nacl versus mgcl2 this is sodium chloride this is magnesium chloride so and how many chlorides there are is just implied by knowing the charges on the cations and knowing chloride's charge so we don't say dichloride or anything like that for just a simple anion here it's just plain old chloride even though there's two of them and just a minute ago we also named this lovely complex anion as tetrachlororate ii ion but again instead of having it as just a standalone anna in here we're going to make it part of a coordination compound here so we have both cation and anion now a neutral compound and in this case then we don't put ion on the end so but this is the name of the anion but again without compounds we name cation first anion second so this is going to go at the end of the name so and we just have to say the name of the cation well this is just plain old sodium just like we had you know nacl this has been sodium chloride well now this is just sodium tetrachloroate ii two words cool and again the fact that there's two sodiums totally irrelevant so if we had na2s this would just be sodium sulfide and notice the two doesn't become part of the name it's just implied for ionic compounds based on you knowing the charges of cations and anions how many there's going to be in that balanced formula for a neutral compound all right in this last example instead of giving you the formula and asking for the name now we're going to give you the name and ask for the formula and what's going to make this one just a little bit challenging is both the catian and the anion are both complex ions so but as you'll find out going from a a name to the formula is actually a little bit easier at least for an individual complex ion putting the two together will be a little bit challenging so hexa amine nickel 2 well nickels the metal ion so that goes first in the formula hexaamine means there are six ammonias here and then it's nickel two and being nickel two that means overall it's gonna have a plus two charge since ammonia is neutral and nickels plus two all right so then over here we got hexacyanoferates and ferry that's iron so we'll start off with fe and then hexacyano that means there are six ligands and those are minus one each you'll notice that all the negative uh ligands that all the organs that are negatively charged always going to end with the letter o like cyano chloro fluoro so carbonado oxalato so on so forth so just a nice convenient way of remembering you know and notice aqua and amine don't end with an o and they're not negatively charged so but this is hexacyanoferate two and in this case the cyanoligans are minus one each so the iron here's plus two so overall this must have a minus four charge and so just like with you've got simple cations and simple anons you have to adjust the number of cations and anions to get an overall neutral compound so if this is plus two and this is minus four we don't have a neutral compound until we put a big fat two right there and now we've got a neutral compound so just be the same as if you had something like nas well again if you're going to get the proper formula for sodium sulfide you gotta realize that sodium's plus one sulfides minus two these aren't going to balance you gotta until you put the two right there so the the cations and anions balance perfectly to a neutral compound so that's the same kind of thing we did right here we had to figure out the overall charge on the cation overall charge on the complex anion and then balance out the formula by putting a 2 subscript right here but here's the overall formula for this lovely coordination compound now if you found this lesson on naming complex ions helpful then a like and a comment letting me know are pretty much the best things you can do to support the channel now in the next lesson we're going to start going through isomers and it's going to require your best mental focus so if you need to grab a little coffee before joining me in that next lesson then i'd highly recommend doing so happy studying