Naming Coordination Compounds

Hey guys. In this new video we're going to take a look at the rules involved in naming coordinate compounds or coordinate complexes. So, we're going to say in the early days of coordination compounds they were named after the people who first prepared them or for their brilliant colors, remember, we said that some of these coordinate compounds that they display really interesting colors because again they're paramagnetic, at least in terms of the central metal cation. So, for a lot of them it creates these different types of electromagnetic radiation, which develops into different types of colors. Now, we're going to say today the naming of these coordinate compounds is similar in some way to the way we name ionic compounds but there's a set of rules, we need to follow. So, rules for naming, we're going to say that the metal cation is written before the nonmetal anion, we're going to say, if the metal, if the metal is a transition metal that has more than one charge, then we have to use a Roman numeral. Remember, certain transition metals only have one charge, for example, zinc is always plus 2, cadmium is always plus 2, silver is always plus 1, these don't require us to use Roman numerals for them, next, we're going to say the only space in the name should appear between the positive cation and the negative anion portion. So, remember, we're talking about a coordinate complex, it's made up of two things, it's made up of your cation, which could just be a metal or the complex ion itself and then you have counter ions, which are the anion and that could be a nonmetal or could be a negative complex ion as well, we're going to say for the complex ion portion, we're going to say, neutral ligands are written before anionic ligands so the neutral ones like NH3 or water are written before the negative ones here, I've compiled a quick list of the most common types of each. So, we have our neutral ligands and we have our anionic ligands, we can also add to this list en, okay? En this would just be our ethylene diamine, okay? We're going to say here and the formula for whole complex is placed inside of brackets. So, remember for complex ions we always use brackets around it, we're going to say within the complex ions the ligands are names in alphabetical order before the metal ion, we're going to say the anionics drop the -ide and add -o after the root name. So, we're going to see different ways of naming things. So, water is aqua, NH3 is amine, we're going to say here, CO is referred to as a carbonyl, big organic term, when you get to organic to learn more about carbonyls, we have NL, which is nice nitrosyl and then we have Fluoro, Chloro, Bromo, Iodo, Hydrox, hydroxyl, which is OH- and cyano CN minus. Now, a numerical prefix is used to determine the number of a particular ligand. So, if you had two of these this would be diamine, if you had three waters then be triaqua, right? So, you have di, tri, tetra, penta, hexa, if you're having this these different numbers. Now, the complex ion is an anion, we replace the ending of the metal name and add -ate. So, iron becomes ferrate, copper becomes cuprate, lead becomes plumbate, silver becomes argentate, so notice here that these names are similar to their symbols, at least to their shorthand way of writing them, why? Because these are the Latin names and we're just changing the latin names and putting an -ate at the end. Now, how exactly do we name these, let's combine all the rules that we just learned. So, let's first take a look at this thing, this part that's in brackets, this is our complex ion. So, this whole thing is our complex ion in here, looking at the complex ion you see that the metal is written before the ligands, okay? So, titanium is written first, next, what you should realize is NH3 is a neutral ligand, we said that neutral ligand should be written before the anionic ligands the negative ones, which it is because Br is negative 1. So, that's our complex ion and then here this Br that's on the outside, this is our counter ion, altogether this is our coordination complex.

Now, that we have to try to name this thing, alright. So we're going to say here, let's talk about the different things involved, we're going to say here though, we're going to say, here we have, what we have this NH3 and there's four of them. So, that's tetra because there's four amine a, we have inside the complex, we have Br, okay? So, the one inside the complex and we call that bromo, okay? And there's two of them so that dibromo but we look at B for alphabetical order, remember, we're naming the ligands inside the complex alphabetically, then we have a Br that's on the outside, that is a counter ion, when it's a counter ion it's not bromo it's bromide. So, we have to talk about this titanium, what is the charge of titanium, it's a transition metal, it's not zinc, it's not cadmium, it's not silver. So, we know that it doesn't have just one charge, it has multiple charges, we have to identify which one it has. So, we have to solve for its charge. So, we're going to say that it's x then we're going to say here, what we're going to say that ammonia has no charge so it's 0, halogens are negative 1, treat it like a math problem, solve for x. So, we're going to say here, one titanium, which is x plus four ammonias, each one is 0, plus two bromines inside the brackets, each one is negative 1, plus one bromine on outside the brackets is also negative 1. So, this drops out. So, x minus 2 minus 1 equals the charge of 0. So, x equals plus 3, so this is titanium 3 that we're dealing with, now we're going to name all of it together. So, when the metal is inside of the bracket it's part of the complex, when the metal is part of the complex it's going to be named after the ligands. So, let's look at the ligand, the ligands are NH3 and Br. So, named them alphabetically, do not look at the numerical prefixes to determine alphabetical order, they don't count, we're looking at the A and we're looking at the B to determine the alphabetical order. So, this would be tetraamine dibromo then we're dealing with titanium now, titanium 3 and then we have a bromide on the outside bromide, okay? So, that's the name, this is alphabetical order A before B, then the metals named after the ligands then the counter ion is named last, since the counter ion is a nonmetal we change the ending to -ide. So, this would be the name of this first coordinate complex that we took a look at, let's look at this next one here, in this next one, let me take myself out of this last one guys, for this one here, what do we notice, here the brackets, in this one the complex ion is an anion and remember, what do we say, we said that if the complex ion is an anion, the negative portion, we replace the ending of the metal name and add -ate, okay? So, first things first the complex ion, okay? We know it's negative why do we know it's negative because Na is plus 1. So, this whole thing must be minus 1, okay? So, it's the negative ion form you can look at it like that if you want. Alright, so platinum is involved. So, we would change the ending of platinum to -ate. So, we're going to say that this part gets transformed to -ate, so it becomes platinate, we still have to figure out the charge of platinum. So, we treat it like a math problem, we know, this is plus 1, we don't know what this is, this is x, this is a neutral ligand so it's 0, halogens are minus 1, treat it like a math problem, we have one sodium, that's plus 1 plus platinum plus 3 ammonias, each one is 0, plus 5 chloride, each one is minus 1 equals the charge of 0, 1 plus x this drops out because it's 0, minus 5 equals 0 combine the plus 1 and the negative 5 together, that gives me negative 4. So, we're dealing with platinate four. Alright, so let's try to name this. Sodium is written first. So, we're going to say that this is called sodium. Alright, then we have to look at the ligands, ligands within the complex ion, the ligands are written first and remember we follow them by alphabetical order, we have 3 ammonia. So, that's triamine and then we have chlorines, we have five of them. So, that's Penta, since it's inside the bracket it's part of the complex ion. So, it's not chloride it's chloro. So, remember the numerical prefixes are not used for alphabetical order, that's not what we're looking at, we're looking at the A and the C. So, alphabetically A comes before C. So, that'd be sodium. Remember, the only space is between the cation and the anion. So, sodium space triamine, pentachloro platinate 4, okay? So, that would be the name of this complex, that's coordinate complex. So, as you can see there's a lot of detail that goes into naming these structures. So, it's imperative that, one, you guys get down the basics of what do we call certain ligands within this compound and from there follow the rules, if they're halogen is inside the complex, what do we call it versus if it's a counter ion. Remember, the alphabetical rules that we follow also remember how we write certain structures, neutral ligands first then the anionic ligands after that, knowing these rules are fundamental because they could ask you to name one or they can give you the name and from the name you need to write down the formula, both ways are incredibly important. So, keep practicing guys.

Hey guys. In this new video we're going to take a look at an example or asked to name a coordinate complex or coordinate compound. So, here it says, give this systematic name for the following formula. So, we have silver, we have sodium, we have cyanide ions, two of them. So, just realize here we have what? we have a complex ion here, and remember when your complex ion is an anion, we change the end of the metal to eight. Now, here we're dealing with silver. Remember, with silver what's the name is argentate, here technically silver is always 1+ but we'll put argentate 1 to illustrate that it's always 1+. Now, sodium is the first metal there. So, we're going to name is sodium and then remember, we name the ligand before we name the metal and remember there's a gap of space between the cation portion and the anion portion. So, this will be sodium dicyano, di because there's two of them cyano because it's Cn, argentate 1. So, this would be what we have. Now, realize why is the formula written that way? because remember, sodium's in group 1a. So, it's plus one, which would mean that this ion here would have to be 1- and when they combine they cancel out and that's how we got this formula but why is it 1-, it's -1 because remember, silver is always 1+ and these Cn's are each 1-. So, it'd be 1 plus 2 cyanides, which are each one 1-. So, that's how the overall formula was 1-. So, now that you've seen us do this example try to do the next example on your own, pause the video really quickly, attempt to do it, come back and see how I answer it.

Alright guys, hopefully you pause the video. So, let's take a look at this one, it's tetraaminezinc carbonate. So, just realize here that zinc is a type 1 metal, meaning it only has one charge as always plus 2. So, it's a zinc connected to four amines. Remember, they are neutral ligands. So, they have no charge, zinc is always plus 2 they're neutral so the overall charge is +2, carbonate is a polyatomic ion. So, it's Co3 2 minus. So, we have plus 2, we have minus 2. So, what happens, they cancel each other out, so that would be tetraaminezinc carbonate, hopefully you guys were able to get an answer that was close to this, if you didn't get the exact answer just realize there's a lot again that goes into naming of these compounds because the metal didn't end with an ate we know that this part had to meet a complex ion portion. Now, that we've seen this attempt to do practice question 1 here, do it on your own, see how far you can get with it, come back and see how I named the same exact compound. So, good luck guys.