Allotropes of sulphur

[andrewtretiakov]

Hi all,

As a way of introducing myself I thought about posting some photos of allotropes of sulphur that I have made and a short description of how I made them. I've also included some other experiments involving sulphur.
Hope you like them.

The monoclinic sulphur crystals were made by melting crushed roll of sulphur in an evaporating dish. As soon as the sulphur was all molten the heat was removed and left to cool down. Once the crust started forming on the top layer, a hole was made to remove the rest of the molten sulphur inside it. After further cooling, large needle/rod shaped crystals were revealed once the sample was cut in half.

The rhombic crystals are probably my favourite but it requires the use of a very nasty, toxic and flammable solvent called carbon disulfide. This was done inside a fume cupboard. By dissolving some sulphur powder in the solvent and seeding it a few large crystals were able to grow.

Plastic sulphur is not really an allotrope but the long chain of sulphur atoms allows it be be stretched using your fingers but eventually reverts to the more stable monoclinic form after a few days.

Sulphur was used to cast different materials and make moulds in the past (I think marzipan was made in sulphur moulds). Anyway, I tried making a sulphur fish by pouring molten sulphur in a silicone mould. I've tried making a mould of my metal key but don't have the photo.

One experiment I always like to do is the thermal decomposition of iron pyrites (Iron sulfide) or Fool's gold to produce sulphur which clearly condenses as yellow dust in the cold parts of the tube. The truly interesting part is that when relatively larger pieces are heated they crack and explode making very loud noises inside the test tube. A process called decrepitation.

And finally, since sulphur is very closely related to sulphuric acid, the last one involves pouring a small amount of concentrated sulphuric acid (CORROSIVE) wearing gloves over some table sugar in a beaker inside a fume hood. The powerful dehydrating effect is extremely exothermic causing huge amounts of steam, carbon dioxide and sulphur dioxide to be produced leaving behind a carbon foam with trapped gases that increases substantially in volume.

Thank you,
A

[mgritsch]

Hi Andrew and welcome
Yes sulfur is an element with many faces, some of them are really beautiful. I particularly like the nice big crystals in the RBF (from toluene?).
And there is so many inorganic and organic compounds, it never ends

As most of the content here at illumina is German, do you happen to speak (or at least read ) German?

[andrewtretiakov]

Hi
thanks very much for the warm welcome and kind comments. The nice long crystals were formed by cooling the molten sulphur very slowly in an evaporating basin not a RBF sorry (no solvent necessary either).
I know, the chemistry of sulphur and sulphur compounds and molecules is never ending!

Unfortunately, I don't speak German and I can read only a bit if it's chemistry/science related then I can get the general idea. I can manage with google translate for the rest. I do understand that your site is mainly in German and I apologise if I post in English. I will try to translate to German in my upcoming posts if that's OK.

[mgritsch]

No worries, English is fine for us. I guess better a clear and understandable English text than something messed up by a translator by the way: deepl.com is way better than google translate!

If you find something interesting written here but translation with google doesn’t work for you just ask.

[andrewtretiakov]

Excellent!
Thanks so much for the recommendation and help.
Much appreciated.

[lemmi]

Hello Andrew, welcome to Illumina!

I agree that there Is no problem wirth posts in English - as long as you can cope with my limitated ability to respond in English ...

This forum has the following structure:
We use certain formal requirements for Experiments that are aimed top be "published" in the section "Illumina Artikel". They are to be found here. Experiments that adhere to this form should be placed in the "Artikelschmiede", where you made your posting. After peer review and discussion a Moderator Will Pass Thema top the "Illumina Artikel" section. So all the articles you find there a reviewed and confirmed. By this way we aim at having a collection of reliable informations about how to perform specific chemistry experiments.

Of cause you can post experiments in a individual manner without using the form required for articles. So the adequate subforum would be the "Spielwiese" (playground) here.

The other sections of "Chemie und Physik" are for discussion of different topics without documentation of experiments or formal requirements (as long as they don't go against pur forum rules, we don't like questions about illegal topics like explosives or psycoactive drugs here).

As you said in your opening post that you wish to introduce yourself by this thread, I will pass it to the "User-Vorstellung" section.

Tell us a littlebit more about yourself! Where do you live, what Is your connection with chemistry, any special interests. ..

[andrewtretiakov]

Thank you so much for the warm and kind welcome and help. Trying to navigate through the various forums and adjusting to the formats.

I'm incredibly lucky to find this forum and I think it's absolutely great! I now feel surrounded by like minded people.

Thanks again for the welcome and I hope I don't disappoint.

Cheers,
A