Sciencemadness Discussion Board

A remarkable discovery...

Polverone - 15-7-2002 at 20:02

Today I went to Ace hardware to pick up some more hydrochloric acid. Alas, they were out. But while browsing through the other materials I encountered something totally unexpected: calcium carbide! It said on the can that it was intended for miners' lamps. I thought this stuff had gone the way of the dodo and nitric acid from the drugstore.

I bought a can because you just don't see that every day. I'm still not sure what I can do with it that won't blow my fool head off, but wow. I have no idea what inspired them to stock this. There sure aren't any mines or miners around here.

raistlin - 16-7-2002 at 06:25

They might have stocked it for use in camping lanterns... And is it pure or what?


BrAiNFeVeR - 16-7-2002 at 10:43

I don't think purity matters a lot with this, since all you're using is the gas (acetylene) that evolves from reaction with water ...

H2O + C2Ca = C2H2 + CaO

kingspaz - 25-7-2002 at 02:22

about the purity, its made by mixing excess carbon with CaO in an arc furnace which operates at around 2000*C!
CaO + 3C ----> CaC2 + CO
the stuff can't be purified very easily since it reacts with water present in the atmosphere and it also doesn't really need purifying for miners lamps. it contains a fiar bit of carbon and other bits of crap. i have about 150g of it.
it can be used to prepare double salts also though. speaking of which does anybody have a definate formula for double salts?
i thought it was AgC2.2AgNO3

vulture - 6-8-2002 at 01:30

Small correction:

CaC2 + 2H2O -> C2H2 + Ca(OH)2

Not really

PrimoPyro - 8-8-2002 at 18:31

kingspaz is correct.

The reaction proceeds at 2000C and Ca(OH)2 is not stable at that temperature, but dehydrates to CaO + H2O. The H2O boils away and the CaO forms (slag?) at the bottom of the reaction mixture.


madscientist - 8-8-2002 at 18:43

I think vulture was thinking of tossing CaC2 into a large quantity of H2O.

CaC2 + H2O ----> CaO + C2H2
CaO + H2O ----> Ca(OH)2

So I guess he was correct...


PrimoPyro - 8-8-2002 at 18:46

Why cant I edit my post? Is this option not available to users?

I would have just edited this into my last post, but since I can't I'll post my reply as a reply:

FUCK! Haha, you're right, I'm just confused today it seems....


madscientist - 8-8-2002 at 18:55

Haha, something is terribly messed up with the board software. But I'm not about to reinstall it - the MSDB has had been at ezboard, on UBB, and now on this. I'm not up for another software change. :)

Yeah, it's annoying.

vulture - 9-8-2002 at 08:38

Errm, adding calciumcarbide to water is something different than reacting CaO with carbon no? :P

PHILOU Zrealone - 15-8-2002 at 13:30

CaO + 3C + heat --> CaC2 + CO
So CaC2 is poluted with both CaO and C (uncomplete reaction like all endothermic processes); since it reacts with air moisture, you also have some Ca(OH)2 in the impure CaC2.
Pure product is white cristalline and cost a lot since it is made from metathesis (no easy possible separation from the impure product) from Na2C2 and a salt of CaCl2 (both chemically pure).
Impure product is good but free traces of H2S, PH3, AsH3,...upon contact with water.

CaC2 + H2O --> CaO + C2H2 + heat
CaO + H2O --> Ca(OH)2 + heat

The silver salt nitrato complex is
Ag2C2.AgNO3 and Ag2C2.2AgNO3

A basic form also exists what is only Ag2C2.


My fist post here !

a_bab - 15-9-2002 at 16:23

First of all sorry to bring up an old post.
Philou (aha, so here you are !) is right about Ag2C2.
The copper and silver acetylides are actually copper and silver carbides as CaC2 is calcium acetylide. The acetylides (carbides) of the metals from the group 1 and 2 are very stable at elevated temperatures but unstable in water. Exacly the opposite of the Cu, Ag, Cd : stable in water and VERY instable at temoperatures (read explosives)

Think different

Boob Raider - 16-10-2002 at 12:15

Don't just use it to make acetylene and acetylides ...... CaC2 is a very good reducing agent. It can be use to reduce a variety of things .... I think even ThO2 to Th. I think even the dreaded CS2 can be made by distilling CaC2 and S. Powdered CaC2 with powdered CaO2 should be a fairly powerful mixture.

kingspaz - 24-11-2002 at 14:47

philou? is the Ag2C2 the ligand in these complexes? also do you have any ideas as to the conditions needed to prepare the two complex salts relatively pure?

PHILOU Zrealone - 26-2-2003 at 04:23

Ag2C2.xHNO3 can also exist aside with Ag2C2.xAgNO3!

a_bab, do you have reference about Cadmium acetylide...I have some Cd salts here and I never thought they could be of any use except characterising S(2-)!

Also to mention some of the strongest of all acetylides!
Hg2C2 and HgC2
Because the HG produced is in the gaseous form!

PHILOU Zrealone - 27-2-2003 at 16:28

Not to forget also the explosive
I-C#C-I (diiodoacetylen)!

New OSHA regulation for hcl

NeverSleepy - 28-2-2003 at 06:24

I just learned yesterday that murratic acid connot be stored on store shelves, you will have to ask for it Polv. Home depot stores it outside in the garden section. Ive been wondering why the shelves were dry also.


Polverone - 28-2-2003 at 07:13

No, they were just out of acid at the time. I went back later and they had some. Do you have a link to the new regs that would keep HCl off the shelf? I would believe that this could happen in California, where paint stores don't even sell toluene, but I would be surprised if it were a national thing.


pissabolities - 31-8-2003 at 13:56

When acetylene's bubbled into dilute sulphuric acid which has mercuric sulphate dissolved in it, acetaldehyde is produced. This compound is very volatile(b.p. 20*C)and easily distilled.
Having the stuff poses a dilemma; do you get high off it or mix it with formalin and lime to make pentaerythritol.
'Don't think I'll ingest it, though.
A jet of acetylene, burning in air can produce a very white light, similar to sunlight; replacing metal halide lamps maybe. Skunk cultivators take note; no worries about electricity consumption.
And plants'll love the by-produced co2.

chemoleo - 31-8-2003 at 17:28

sorry for asking something that's been possibly covered already...
but is there a description to make
silver (or Cd, Hg, whatever?) acetylide nitrate? (or related double salts?)?

shadeT - 31-8-2003 at 20:45

i got my calcium carbide from a friend that is a plumber , he gave me 5 kilo's . and i have it now for about two years in sealed contaniers and i still didn't use all of it . it was also used in repeling some animals ( rats , or what .... )

rikkitikkitavi - 1-9-2003 at 11:40

in sweden we can buy CaC2 in well stocked hardware stores.

Its main use is for carbide lamps, but since I read about it beeing used for scaring away moles I had to test that.

Gave some of it to a friend, who had lots of problems with moles digging up his lawm, we put a few pieces in the soil of each pile they dig up it didnt take more than a few days to get rid of them :)

Since he live in a small town it didnt take long for him to convince many of his friends to try it and soon after that the local hardware shop had to make a special order of calcium carbide from his supplier...

(Moles have a very very good sence of smell, and carbide smells awful due to calcium fosphide, reacting to phosphine with water)