Talk:Copper(II) sulfate

Disappearing Mg?

"It can also be prepared by electrolysis of magnesium sulfate [Epsom salts] solution at moderate voltage with a copper anode: this reaction produces hydrogen, copper sulfate solution, and copper hydroxide precipitate."

what happens to the magnesium? MgSO4(aq) + Cu(S) --dc--> h2(g) + Mg(OH)2(s) + CuSO4(aq) would make more sense.

Sounds reasonable; added to the article. Materialscientist (talk) 23:40, 3 April 2010 (UTC)

Random questions

The article states: "In an illustration of a "single metal replacement reaction," iron is submerged in a solution of copper sulfate. Upon standing, iron dissolves and copper precipitates. Fe + CuSO4 → FeSO4 + Cu"

Can anyone tell me if any similar reactions occur with stainless steel or other metals (brass, copper, chrome, etc...), pure or otherwise, in a natural state (i.e. not through electrolysis or other method)? Many thanks - Yes, it is a process called transmetalation (I think). It is essentially a battery, where initially there is no Iron salt, and no copper electrode. In a typical battery, as it looses energy, one electrode is degraded with the metal going into solution, and the other one is built up, with metal coming out of solution. This is essentially a short circuited version of that. Electrolysis would push this the other way, so you could get iron out and put copper in. With any 2 metals, one will go into the solution and precipitate the other out (assuming there is some of the metal to go into solution and some metal to precipitate out). Electrolysis will reverse this. — Preceding unsigned comment added by Black.jeff (talk • contribs) 01:08, 26 October 2011 (UTC)

________________

does copper(II) sulphate conduct electric current?why?

Copper sulfate dissolved in water will dissociate into ions (Cu⁺⁺ and SO₄^--). These ions can conduct electric current. See ionization. Solid copper sulfate would be a poor conductor at best, . RJFJR 00:41, Feb 12, 2005 (UTC)

How can you turn Copper(II) sulfate into copper?

Why would you want to? It would be easier, cheaper, and safer to just buy copper in bulk.

Darrien 07:06, 2004 Oct 24 (UTC)

Electrolysis will work. Also see the entry for copper which will point you to smelting for how to use a reducing agent to do it. RJFJR 00:41, Feb 12, 2005 (UTC)

put a piece of aluminium in the copper sulfate, you should get aluminium sulfate and copper precipitate, filter off the copper, its very high mesh copper powder.

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Does someone have the balanced equation for that decomposition of Copper(II) sulfate into the oxides? RJFJR 00:41, Feb 12, 2005 (UTC)

Assuming this isn't a homework problem...

CuSO₄ · 5 H₂O + Heat (~100°C) → CuSO₄ + 5 H₂O

2 CuSO₄ + Heat (~800°C) → 2 CuO + 2 SO₂ + O₂

4 CuO + Heat (~1200°C) → 2 Cu₂O + O₂

The temperatures required are from memory. I wouldn't trust them enough to include in the article.

Darrien 12:36, 2005 Feb 12 (UTC)

Not homework. I've been out of school too long to remember some of this. First equation easy. Second I got with some work. Didn't think of the third one. The article says the the products of decomposition are CuO and Cu₂O. I read that the first time thought: shouldn't that be CuO and SO₂ (and O₂)? Thank you for clearing that up for me. RJFJR 14:22, Feb 12, 2005 (UTC)

I checked Handbook of Physics and Chemistry 34th edition, Chemical Rubber Company, 1952 (was my dad's) RJFJR 14:38, Feb 12, 2005 (UTC)

• CuSO₄ · 5 H₂O loses 4 H₂O at 110 C, loses 5 H₂O at 150 C
• CuSO₄ decomposes to CuO at 650 C
• CuO decomposes at 1026 C

The above description is right. You get CuSO4 -> CuO + SO3 as it decomposes. First of all, I've done this one before and can attest that you can't get copper. Second, the current equation has O2 and Cu metal as products. This is two reductions and nothing being oxidized. It violates the rules of redox chemistry and can't possibly be correct. If, for example, carbon was added to the reactants, it could feasibly steal an oxygen from the CuO and SO3 to make CO2, and the reduction of the CuO to copper metal would balance with the oxidation of carbon to CO2. I will change the equation. Dormroomchemist 05:20, 10 April 2007 (UTC)

Move

• Support standardization is benefit Tobias Conradi 05:34, 29 Mar 2005 (UTC)

Does anyone mind if I move this page to Copper(II) sulfate (i.e., the IUPAC name)? Currently this is a redirect. Thought I'd better ask since this has been a busy page, although all of the text in this page conforms to the IUPAC name. Walkerma 20:36, 21 Feb 2005 (UTC)

You mean just remove the space in front of the left parenthesis? So far no one seems to have raised an objection. RJFJR 00:11, Feb 24, 2005 (UTC)

Yes I do- it may seem a minor thing, but I'm trying to get all pages standardised on the IUPAC system- nearly all of them are now (see List of inorganic compounds. That way if you type in the correct name, you find the compound. I have added a move request to the page since I was unable to do the move myself. Walkerma 23:01, 28 Mar 2005 (UTC)

This article has been renamed as the result of a move request. violet/riga (t) 18:00, 2 Apr 2005 (UTC)

Americanisation

Can someone please change Sulfate to Sulphate, im not being anti-american but its internationally rcognised as sulphur/sulphate/sulphate etc., my credential to prove my knowledge is that im studying chemistry to AS-Level (hopefully beyond that too) at college

• Sorry, it's internationally recognized as sulfate, including in UK scientific publications. I can't believe the A-level boards haven't caught up with this: they have been incorrectly ramming "ethanoic acid" down everone's throat for years. "Sulphate" is still an acceptable British use, but not in scientific contexts. Physchim62, M.A.(Cantab), Ph.D (Essex) 15:53, 6 November 2005 (UTC)

I'm also studying AS Chemistry, and I know about sulfate being the IUPAC name, but am confused as to why ethanoic acid is incorrect, as it is ethane with a carboxylic acid group on the end, 'ethan' + 'oic acid', no? (I know this isn't relevant to the page, but just confused).

• Acetic acid is simply the preferred name, as it is far more established. Walkerma 04:07, 14 March 2006 (UTC)

Also if you are really british, the title would have no z! changing.

i am currently studying chemistry at A2 level, my teacher mentioned that the name Sulphate is officially being changed to sulfate at some point soon here in britain, also Acetic acid is the 'given' name for the chemical, Ethandioic acid is the name if you break it down for naming so to speak, both can be interchangeable. —Preceding unsigned comment added by 131.111.241.30 (talk) 23:58, 9 December 2007 (UTC)

[Copper(I) sulfate] ?

What's up with the [Copper(I) sulfate] under "Related compounds"? It's just a redirect to [Copper(II) sulfate] anyways... Jamie 09:13, 3 December 2005 (UTC)

• Copper(I) sulfate does exist, but we haven't got round to writing an article on it yet... Physchim62 (talk) 11:30, 3 December 2005 (UTC)

What does the (II) stand for? I imagine it's some kind of secret chemistry handshake, but I found no explanation or link in this article. Pergelator. — Preceding unsigned comment added by 50.43.12.61 (talk) 03:53, 8 August 2013 (UTC)

It is common knowledge in the field of chemistry that it is used to refer to the oxidation state. In this case, it is that of copper in this compound. Plasmic Physics (talk) 08:04, 8 August 2013 (UTC)

Eating copper(II) sulfate or throwing it into the sea?

My Biology teacher once told me that copper(II) sulfate displaces iron in the haemoglobin of the blood, causing anaemia. Is this true, or just a misinterpretation of what's already up on the Wiki about copper(II) sulfate being used in tests for anaemia? Is this behind its 'harmful' rating?

On a similar note, why is it harmful to the environment? What regulations are there for its disposal? Firefly99 10:27, 2 April 2006 (UTC)

I doubt this is true, as I have been informed that it is one of the most toxic compounds we use in A-Level chemistry. I think five grams is enough to kill you almost instantly. It may be possible that the copper ions (its them that's poisonous) displace the iron ions in haemoglobin, but it would have to be very thermodynamically favourable, as there is a lot of iron in blood, and as far as I know anaemia is a big dent in the natural amount. Plus, it is locked quite securely in there. In any case, if it did displace the iron, I would think it very unlikely to cause anaemia, more likely asphyxiation.

As for the disposal; if its harmless to haemoglobin molecules, its a fair assumption it kills most animals, what with haemoglobin being a bit on the common side. Except in lobsters. I guess they're immune. mastodon 20:41, 16 April 2006 (UTC)

The reason behind its blue and white colour

What is the reason behind the change of colours when it has full water content (blue) and when it has been dehydrated, without water (white)?

Crystal field theory. —Keenan Pepper 21:02, 3 April 2006 (UTC)

Toxic

This chemical is toxic, when taken internally, right? Shouldn't the article say so?

I've just found a good article describing toxicological effect of copper sulfate on humans and animals. You should read it - Extension Toxicology Network —Preceding unsigned comment added by Healthycare (talk • contribs) 20:47, 4 February 2010 (UTC)

Feeding Copper Sulphate to Pigs

I don't know if this contradicts the supposed toxic effects of this compound, but they feed this stuff to pigs http://www.cda.org.uk/megab2/general/cuFarm/sec12.htm . I remember when i was a boy my friends dad had a pig farm, and he had a big bag of blue copper sulphate to feed the pigs with. Surely this needs to be mentioned in the article? I used to get jars of it to take home and grow crystals with.

It could be used as a supplement mixed into the food, in trace quantities to prevent copper deficiency, much like ferrous sulfate is used to prevent iron deficiency. Dormroomchemist 07:13, 25 September 2007 (UTC)

It might not have been a feed supplement; if the pigs got their water from a pond, the copper sulphate might have been kept there to put into the pond to kill algae. Copper in the body is needed in such tiny amounts that scooping some out of a big sack to give to animals could very easily lead to a catastrophic mistake. TooManyFingers (talk) 16:01, 7 August 2022 (UTC)

Making Copper Sulphate

Why do you add excess copper oxide to te sulpuhric acid in the production of copper sulphate? —The preceding unsigned comment was added by 222.152.21.198 (talk • contribs) .

I'm not going to do your homework for you, so just think about it. Why would extra copper oxide be easier to separate than extra sulfuric acid? Hint: solubility. —Keenan Pepper 21:52, 13 June 2006 (UTC)

Poisonous?

The article says that copper sulphate is poisonous. However, I am told that it is used against algues in a pond where people are supposed to swim in and where they actually do. Of course it is not completely contradictory to being poisonous, but it should be put in perspective: it seems not to be that poisonous that you cannot swim in water with copper sulphate (a hand full in 50 m3), taking into account that most people swallow quite some water during swimming.

Am I correct?

Ingel 07:50, 8 July 2006 (UTC) (discussion moved to bottom of page by Dirk Beetstra ^{T C} 08:25, 8 July 2006 (UTC))

Definition of poisonous is always difficult, it is all a matter of dose, even water is poisonous. And people in general don't drink from the pond, and indeed, the concentration is very low. --Dirk Beetstra ^{T C} 08:25, 8 July 2006 (UTC)

The NFPA rating is completly off. All MSDS I have on hand say it is 2-0-0. I will change as soon as I find out how to do that. —Preceding unsigned comment added by Xenofonos (talk • contribs) 17:54, 31 October 2007 (UTC)

I am trying to ensure that it says that is to poisonous, but someone else keeps undoing it and I have no idea why. I am sure that there are plenty of children thinking of having a nice copper sulphate lick.

We made a policy decision at WP:Chem that we would not give detailed safety information on any chemical, since this lies outside the scope of an encyclopedia. We do allow links to professional MSDS's and safety information, and if you look in the external links, these are available. What this page really needs is an expansion of the structural information and the chemical properties, if you can find some suitable source material. Thanks, Walkerma (talk) 02:44, 2 December 2008 (UTC)

the change of the color.

why does this substance change color from blue to green when water is added?

It shouldn't. Copper (II) Sulfate forms a light blue solution. If the water has a lot of chloride ions in it, a complex ion may be formed that would make the solution green. --24.16.154.50 00:05, 12 January 2007 (UTC)

Fire resistant?

I read that during the 1906 earthquake in San Francisco, soldiers who guarded the Federal Mint building, tore the tar roofing off the wooden rafters and dipped the rafters with "blue vitriol". What for? Is it fire resistant? Kraxler 17:00, 9 January 2007 (UTC)

Probably because they had heard that it preserves wood. Copper(II) sulfate has long been used as a (somewhat inefficient) fungicide. Copper chromate stays longer in the wood, but has been banned for a long time because it is highly carcinogenic. Tearing the roof tarring off would obviously remove the water-resistance of the wood timbers, increasing their vunerability to fungal rot, but would also mke them more difficult to set fire to: in dipping them in "blue vitriol", the soldiers were trying to avoid rot (which was probably not the most urgent problem at that moment :), but also increased the water content of the timber (reducing the risk of fire). Physchim62 (talk) 16:06, 10 January 2007 (UTC)

Ionic or Covalent

Is copper sulfate a ionic compound or a covalent/molecular compound? —The preceding unsigned comment was added by 71.100.176.25 (talk) 22:43, 10 February 2007 (UTC).

Ionic.

Ben 23:02, 10 February 2007 (UTC)

Thanks, i was trying to find it.

"Sulfate" vs. "Sulphate"

The article uses both frequently. Isn't one form or the other standardized by IUPAC? toll_booth 01:22, 21 February 2007 (UTC)

Sulfate is the correct IUPAC spelling.Lostandcold 01:43, 13 May 2007 (UTC)

Effect on algae

I deleted this sentence from the paragraph on the use of CuSO4 in aquaria: "The algae cell dries out due to copper(II) sulphate being a desiccant." This must be a prank, right? --Jorge Stolfi 143.106.23.149 13:29, 1 April 2007 (UTC)

Image rm

In one of my edits, I removed this image. It is left here is others think that it should be moved back. I just did not see the relevance of the image.--Smokefoot 22:45, 5 June 2007 (UTC)

Copper(II) sulfate crystals at 100x magnification

Copper Sulfate Solution

Can we have a bit about Copper Sulfate in solution please, there isn't much about it on the page and i think there probably should be more, as it can be used as a micronutrient in low molarity, also my coursework is based on the effect of copper sulfate solution on the germination of mung beans, so it obviously has other applications than those listed.

Action as an inhibitor to Catalase

Can someone provide some information on whether Copper Sulphate is a (non)competitive and (non)permanent inhibitor to Catalase. Some websites say it is comptitive, but some say otherwise. Can someone give some clarification to this, and also add it to the article? Matwilko (talk) 12:06, 14 December 2007 (UTC)

Structural Formula

Does anybody know the structural formula of copper sulfate? I've seen:

    O

Cu-O-S-O

    O

But it doesn't seem to work: it fails in terms of fulfilling the Lewis structure

NOTE: in that diagram above, the two floating Oxygens should be beneath and above the Sulfur atom

I have another stupid question - is copper sulfate a polar molecule?

Noahdabomb3 (talk) 23:39, 15 December 2007 (UTC)

Copper sulfate is not a molecule, that's your problem.--Smokefoot (talk) 02:24, 16 December 2007 (UTC)

Baby Formula?

For real, or is this vandalism? It seems unlikely they'd put poisonous copper compounds in that is all. 88.106.19.97 (talk) 21:26, 2 March 2008 (UTC)

add this please

a pirahna solution of H2SO4 and H2O2 (super acid be careful) will oxidise copper into CuO and react with the H2SO4 to make CuSO4. —Preceding unsigned comment added by 68.101.30.173 (talk) 18:54, 14 May 2008 (UTC)

Use in organic farming

Is it true that this compound is allowed in most schemes of organic farming? Badagnani (talk) 05:18, 5 June 2008 (UTC)

Antidote

Why is there nothing on this page about use of CuSO4 as an antidote, considering that it is listed on the antidote template that also appears at the bottom? Mr0t1633 (talk) 16:53, 10 August 2008 (UTC)

Available commercially

This sentence seems a bit odd.

"Since it is available commercially, copper sulfate is usually purchased, not prepared in the laboratory."

Surely many compounds are available commercially.  ??

Wanderer57 (talk) 18:08, 8 October 2008 (UTC)

I find that important. That something may be commercially available does not imply that the synthetic chemist will prefer to buy it. Examples include lithium diisopropylamide, tetrakis(triphenylphosphine)palladium. These compounds are either used on a small scale, are easily prepared, or do not keep well, among other things. On the other hand, some compounds are not available widely, or at all. While we use different headers, "preparation" usually refers to a semi-large scale - gram-<1 kg scale. "Synthesis" refers to small quantities, perhaps less than 1 gram. "Production" refers to industrial scale - tons, perhaps. --Rifleman 82 (talk) 18:34, 8 October 2008 (UTC)

Thank you. I'm guessing here but would it be closer to the mark if the sentence was:

"Since it is available commercially at very low cost, copper sulfate is usually purchased, not prepared in the laboratory."

Wanderer57 (talk) 18:54, 8 October 2008 (UTC)

Not archaic terms?

"Archaic names for copper(II) sulfate are "blue vitriol" and "bluestone"." Except the source given only describes these other names as "Synonyms". "Bluestone" is still very much in use - Google gives 127,000 hits for bluestone copper. SmithBlue (talk) 07:43, 18 November 2008 (UTC)

In the field of chemistry, those terms are certainly archaic; a chemistry text would correctly call them archaic, if they were even mentioned there. But in some other fields, older terms are still used. The reason is probably always the same: "That's what we've always called it, few or none of us are chemists, and if we changed the name (even to make it clearer or more correct) we believe the change would cause confusion." They are choosing to use an archaic term for convenience, and in their context that's not wrong. TooManyFingers (talk) 16:17, 7 August 2022 (UTC)

The other way to look at it is that these are simply the common names, just as water isn't normally called an IUPAC name. That raises an interesting question: if a common name becomes somewhat uncommon, what is its status? TooManyFingers (talk) 16:37, 7 August 2022 (UTC)

Solubility

In Some Properties of Copper Sulfate they say that copper sulfate is pretty soluble and if the pH is kept less than 7, the pH would have a small unpredictable effect. If a lot of sulfuric acid is used the solubility will be decreased by the addition of a common ion "(SO4)^-2" but this would require a very low pH. On the other hand if the pH is significantly greater than 7 copper hydroxide Cu(OH)2 would precipitate but under more or less neutral conditions, i.e. pH ~7, pH has little effect on the solubility of copper sulfate.

As per TOXICOLOGICAL PROFILE FOR COPPER, copper sulfate is soluble in methanol and slightly soluble in ethanol. If anyone finds this information worth for inclusion into the main article, please include it. J.D. (talk) 20:39, 4 February 2010 (UTC)

Paramagnetism

The Ferrofluid article claims copper(II) sulfate is paramagnetic. If so, it should be mentioned in the article. JKeck (talk) 02:06, 5 September 2010 (UTC)

It says it about aqueous solution. Ionic solutions are paramagnetic in general. What is remarkable about it? Also many inorganic solids are paramagnetic because of non-stoichiometry (e.g. intrinsic fluctuations of vacancies and interstitials). Materialscientist (talk) 02:32, 5 September 2010 (UTC)

History

Has anyone information on the use of the compound in agriculture in the past? I found the history of the Bordeaux mixture and there is copper sulphate indicated already in use in 19th century. I think it would an interesting addition to the article.--Dia^ (talk) 12:13, 9 April 2011 (UTC)

Merge from copper(II) sulfate pentahydrate

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

---

Closed as merge. --John (talk) 20:23, 20 October 2011 (UTC)

We usually do not separate articles based on the degree of hydration. The present article on the copper(II) sulfate is mostly about the hydrate. Not sure how to handle the chem boxes, but we should lead with the pentahydrate since this appears to dominate usage. The anhydrous form is more of a curiosity. Just a thought. --Smokefoot (talk) 13:17, 3 October 2011 (UTC)

I agree. Copper (II) sulfate almost always refers to the pentahydrate. There is no need for a separate article. I didn't see anything in the separate article that wasn't already in the main article. Most chembox's list all hydrates in order of lowest hydrate to most hydrated form; this article should follow the same procedure to remain consistent with other articles. Explodo-nerd (talk) 15:59, 3 October 2011 (UTC)

Chemboxes shouldn't list information on the hydrates unless they are important. It's time we seperate the two, have Copper(II) sulfate cover the topic in a general sense, and have Copper(II) sulfate pentahydrate cover the pentahydrate in more detail. It's not a reason to get rid of the article, because we don't usually write ones on hydrates. Plasmic Physics (talk) 22:00, 3 October 2011 (UTC)

Could you tell us how you intend to expand this article, and how it would be viable as a stand-alone? I can't think of much to say about this compound which should not belong in copper(II) sulfate. Talk about color and dehydration? That goes in the structure and properties section of copper(II) sulfate. Talk about this compound as a mineral? Goes into the occurrence section of copper(II) sulfate. --Rifleman 82 (talk) 23:17, 3 October 2011 (UTC)

Instead of copying all the details across, I was hoping to gradually move it over. Make Copper(II) sulfate about the anhydrous and aqeuous forms, only summarizing the hydrated forms. Make Copper(II) sulfate pentahydrate about the more systems, and behaviour of the hydrate. Plasmic Physics (talk) 00:03, 4 October 2011 (UTC)

The copper sulfate article is not excessively long. Why do we need to split it off? --Rifleman 82 (talk) 00:33, 4 October 2011 (UTC)

To clarify to the lay person that there is a difference, lest they should think it is one and the same. For instance, anhydrous copper(II) sulfate may cause skin burns due to it hydrating exothermically. It is supposed to clear confusion like that which exists between Hydrochloric acid and Hydrogen chloride. Plasmic Physics (talk) 01:21, 4 October 2011 (UTC)

In terms of process: Plasma, it might be a good idea to stop the editing these articles until we achieve some sort of consensus. Otherwise we have a moving target. There are thousands of other articles to work on, so if you are feeling in an editing mood, there's lots of material. With respect to the discussion at hand, we do not separate the hydrates for other metal salts from their anhydrous forms. The precedents are probably in the hundreds (most of the late metal halides, nitrates, sulfates, etc). In my opinion, such a separation would confuse most readers. We would not subdivide articles based on the exothermicity of their hydration reaction, so that comment is probably not relevant in my opinion. But let's see if we can get some other input? --Smokefoot (talk) 02:34, 5 October 2011 (UTC)

With no disrespect to anyone, I consider most splits and merges as waste of time, unless the articles are too long or overlap too much. My wild guess is the split is simply driven by the efforts of Plasmic Physics to tidy the chemboxes. Materialscientist (talk) 02:41, 5 October 2011 (UTC)

I see no need for two articles. IMHO the article should focus on the pentahydrate, as the anhydrate is just a curiosity - people typing 'Copper sulfate' into WP are looking for the pentahydrate. Chris (talk) 07:58, 5 October 2011 (UTC)

Nobody's commented for about 2 weeks. I've asked an uninvolved admin to close this discussion. --Rifleman 82 (talk) 16:44, 20 October 2011 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Image

Is it correct to call the image a crystal or is it some crystals? Rich Farmbrough, 19:11, 7 February 2012 (UTC).

Citation needed

I added a Citation Needed tag in the Chromated Copper Arsenate paragraph of the "herbicide, fungicide and pesticide" section. No citation was listed, and most MSDS that I could find for CCA treated wood list Copper Oxide as the copper source, and most Copper Quaternary and Copper Azole (used now instead of CCA as CCA is being phased out) MSDS list Copper Carbonate as the copper ingredient. All other MSDS that I could find simply listed "proprietary copper compound" or simply "copper". I couldn't find any MSDS listing Copper Sulfate Pentahydrate as an ingredient in Chromated Copper Arsenate, Copper Quaternary, or Copper Azole treated lumber. Harperska (talk) 04:50, 3 March 2013 (UTC)

small typo in side bar

in the side bar it says "< 650 °C decomp"

this should be be written with "> 650 °C decomp"

"< 650 °C decomp" means "decomposes at temperatures below 650 C" (i.e. the decomposition temperature is unknown and 650 is an upper estimate), whereas "> 650 °C decomp" means "decomposes at temperatures above 650 C"; both are Ok logically, so please provide a reference for your correction. Materialscientist (talk) 02:11, 11 July 2013 (UTC)

Removed the '<'. VMS Mosaic (talk) 01:51, 11 July 2013 (UTC)

I found a reference for the decomposition of copper(II) sulfate at 560 deg. C. I am unsure how to properly cite it for the purposes of this page but I found the information via my institutions access to the online version of the CSC (which the side bar references anyways). For others with access it can be found under "Physical Constants of Inorganic Compounds" 4-62 and entry number 998.

Solubility in Water

On this Wikipedia page pentahydrate solubilities in water are 316 g/L (0 °C), 2033 g/L (100 °C) and anhydrate solubilities in water are 243 g/L (0 °C), 320 g/L (20 °C), 618 g/L (60 °C) and 1140 g/L (100 °C). I think these data should be changed and the reasons are as follows. First of all, the data are expressed in g/L but we are not sure if it is the weight of solute present in a given volume of solution or solvent and we also need to know the density. Besides, volume measures depend on temperature. Secondly, at 0 °C and 100 °C copper sulfate may not exist as pentahydrate. According to Mullin’s book, the transition CuSO₄•5H₂O⇌ CuSO₄∙3H₂O occurs at 95.9 °C and above that temperature the solid phase consists of mixture of pentahydrate and trihydrate or only trihydrate. Finally, according to the solubility data from Detherm, the anhydrate solubilities on Wikipedia page are not correct.

I downloaded all the solubility data of copper sulfate from Detherm and converted all the units to molal. To avoid confusion in the case of hydrated salts dissolved in water the solute concentration always refers to the anhydrous salt. The Figure 1 is the comparison of data from DETHERM and the data from Wikipedia and the average solubility at each temperature based on Detherm data were calculated to give the solubility curve in Figure 2. Finally the solubility data I obtained based on data from DETHERM are 1.09 molal (10°C), 1.31 molal (20°C), 1.56 molal (30°C), 1.80 molal (40°C), 2.12 molal (50 °C), 2.48 molal (60°C ), 2.95 molal (70°C ), 3.42 molal (80 °C).

1

2

--Baihuiqian (talk) 17:22, 18 February 2014 (UTC)

Conventionally, solubility is expressed in g/mL which are units of molarity. Grams are always a unit of mass, never of weight; thus, density seems to be irrelevant (solubility is a measure of concentration anyway). Volume does vary by temperature; thus the solubility at different temperatures is reported. The second point seems sound, but changing the units to molals will not change the properties of Copper(II) Sulfate. As for the inaccuracies, such things can be corrected.

Pertaining to the first graph, the y-axis label states that the units are molals (molality); whereas, the legend states the units are g/L (molarity). I know not which units the data are and must therefore discard the graphs as an irrelevant comparison. If I have erred in any part of this statement, please do not hesitate to tell me. 184.155.150.103 (talk) 04:10, 30 September 2015 (UTC)

References

The average reader of this article wants to know what mass of copper sulphate crystals will make a saturated solution in 1L of water at room temperature. I had to go elsewhere for this information which was extremely frustrating. What the hell is a molal anyway? Polymath uk (talk) 20:49, 18 January 2023 (UTC)

Will add solubility of the pentahydrage in g/100 mL, thank you. Keres🌕Luna ^edits! 20:28, 23 January 2023 (UTC)

5300 Reports on copper sulfate (pentahydrate) and counting...

As of today, according to Chemical Abstracts. --Smokefoot (talk) 17:40, 12 May 2015 (UTC)

Melting Point

The melting point listed is not really accurate, or rather, is presented in an awkward way. The Chemical properties section does address this a bit, but not clearly. Google searches are spitting back "cards" with 230F listed as the melting point. This value is closely related to water loss (dehydration), but not melting. Emphasis should be placed on anhydrous CuSO4 decomposing BEFORE it has a chance to melt. This should be fixed by someone with more time on their hands and experience editing wikipedia. Thanks! --??

The decomposition temperatures in the "Chemical properties" section are inconsistent with those in the chembox. Another source confirms 650 C as the decomposition temperature, but says that the products are CuO, SO2 and O2 rather than CuO and SO3. Which is correct? --Jorge Stolfi (talk) 00:49, 18 August 2016 (UTC)

Copper(II) or copper (II)?

The article seems to be inconsistent in its usage of Copper(II) and Copper (II) to describe the charge of the copper ion in this compound. Should the space be present in all occurrences or be deleted from all occurrences? — Preceding unsigned comment added by 165.91.12.78 (talk) 02:03, 7 October 2016 (UTC)

The manual of style says no space ie copper(II). Graeme Bartlett (talk) 03:53, 14 March 2019 (UTC)

External links modified

Hello fellow Wikipedians,

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Images of rare forms

Today I moved the pictures of anhydrous copper sulfate to a gallery at the bottom. The vast majority of readers will be seeking information on the pentahydrate. Also the mineral forms are more esoteric than anything seriously impacting the everyday world. But in case anyone objects, that's what happened and all can be reversed or discussed. --Smokefoot (talk) 21:43, 4 December 2016 (UTC)

Niche Uses: Antisepctic Concrete additive

"in building it is an additive to concrete to provide water resistance and to make it antiseptic."

The article on Antiseptics states that antiseptics are applied to the skin or other living tissue.

Who in the world decided it would be a good idea to disinfect their wounds with concrete?

I'm changing it to "in building it is used as an additive to concrete to provide water resistance and disinfectant qualities." I don't really like the wording, so hopefully one of you could figure out a better way to say it. — Preceding unsigned comment added by Wertyu739 (talk • contribs) 16:21, 28 January 2017 (UTC)

External links modified

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I have just modified 2 external links on Copper(II) sulfate. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20101221162804/http://www.skylighter.com/fireworks/how-to-make/blue-copper-fireworks-stars.asp to http://www.skylighter.com/fireworks/how-to-make/blue-copper-fireworks-stars.asp
• Corrected formatting/usage for http://www.npi.gov.au/database/substance-info/profiles/27.html

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Copper sulphate powder

How can we get copper sulphate powder instead of crystal Vikas bafna (talk) 20:57, 9 November 2017 (UTC)

Copper sulfate pentahydrate dissolution is endothermic not exothermic

Currently the article states "The pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue. It exothermically dissolves in water." Dissolving the pentahydrate in water decreases the temperature of the overall solution, i.e. the dissolution is endothermic. This is discussed in various chemistry lab texts online, like http://www.dynamicscience.com.au/tester/solutions1/chemistry/energy/cuso4soln.html and https://chemrevise.files.wordpress.com/2015/04/3-12-hesses-law.pdf. In contrast, the anhydrous CuSO4 salt dissolves exothermically, i.e. the solution gets hot. Mccomstock (talk) 14:59, 28 September 2018 (UTC)

and copperhydrogen sulfate?

copper hydrogen sulfate must exist as Potassium hydrogen sulfate exists. how does that look like? maybe one needs a freezer to crystalline it. use a 1mol hydrate and 1mol concentrated h2so4. sour copper sulfate. what is it Wikistallion (talk) 07:08, 23 December 2018 (UTC)

Just because a different substance exists, it has a name, appears in patents or even in databases[1] does not mean that the substance actually exists or has ever been made. It may be that copper sulfate and supfuric acid are more stable separate. I did a search for this substance and it does not appear to be real. It may be termed a bisulfate (or with ph) or acid sulfate. The atom work structure database does not show any acid salts, but there are basic copper sulfate salts. Graeme Bartlett (talk) 04:11, 14 March 2019 (UTC)

Environmental toxicity section

In the "Environmental toxicity" section, there is nothing about it's Environmental toxicity ! It only talks about distribution. Please would someone knowledgeable add this information ? Darkman101 (talk) 16:59, 31 July 2019 (UTC)

Datasheets redirecting to a for sale domain

Currently the domains of the websites that are in the Safety Data Sheets section are no longer active and are for sale.

(Just now made a wikipedia account, don't know how, or even if I can change this) BlitzTheSquishy (talk) 00:11, 7 September 2023 (UTC)

 Fixed. Bernanke's Crossbow (talk) 03:18, 6 February 2024 (UTC)

Spelling of Sulfate/Sulphate

A number of IP interventions, which I assume to be from the same editor in Tamil Nadu, have been made to cyhange the spelling of Sulfur and related words to the tradional British spelling of Sulphur. Whatever the variety of English that has been chosen for the article as a whole, scientific articles follow IUPAC conventions when using names of elements. In this case the conventional spelling was also adopted by the Royal Society of Chemistry in 1992. This is not a dispute about England versus America but of general scientific clarity, consistency and consensus.  Velella  ^{Velella Talk}   16:53, 25 March 2024 (UTC)

The Chemistry naming conventions match what you have said. This shouldn't even be a matter of debate based on our current guidelines: WP:SULF is the direct link. Reconrabbit 18:06, 25 March 2024 (UTC)

Obviously, per SULF wikipedia site consensus based on multiple national and international standards from relevant organizations. DMacks (talk) 18:31, 25 March 2024 (UTC)