Sciencemadness Discussion Board

Determining of a compound is an acid, base or neither using SMILES

SuperOxide - 20-2-2025 at 05:43

I'm trying to automate something programmatically that requires me to lookup a compound by its CAS and determine if it's an acid, base or neither by the SMILES string.
I could try to use the chemical formula, but I ran into issues with that as well.

Note: The below data is pulled from Avery's GHS endpoint, which returns data from Chemwatch (according to Avery).

Here are some examples:
Code:
./analyze.sh 74-89-5 methylamine CN CH<sub>5</sub>N 7664-93-9 sulfuric_acid S(=O)(=O)(O)O H<sub>2</sub>O<sub>4</sub>S 79-24-3 nitroethane N(CC)(=O)=O C<sub>2</sub>H<sub>5</sub>NO<sub>2</sub> 7647-01-0 hydrochloric_acid Cl ClH 10035-10-6 hydrobromic_acid Br BrH 10034-85-2 hydriodic_acid I HI 7664-38-2 phosphoric_acid P(=O)(O)(O)O H<sub>3</sub>O<sub>4</sub>P 110-86-1 pyridine C=1C=CN=CC1 C<sub>5</sub>H<sub>5</sub>N 7664-41-7 anhydrous_ammonia N H<sub>3</sub>N 1336-21-6 ammonium_hydroxide [NH4]O H<sub>5</sub>NO 1310-58-3 potassium_hydroxide [K]O HKO 1310-73-2 sodium_hydroxide [Na]O HNaO 497-19-8 sodium_carbonate C(=O)(O)O.[Na] CH<sub>2</sub>O<sub>3</sub>.2Na 144-55-8 sodium_bicarbonate C(=O)(O)O.[Na] CH<sub>2</sub>O<sub>3</sub>.Na


- Determining if its an acid isn't as simple as checking if the formula or SMILES starts with an H, since the Hydrogens in SMILES are implied, and the elements in the formula (far right column) are in alphabetical order.
- Determining if its a base isn't as simple as looking for an OH group, since that wouldn't account for amines. Looking for [Na/K/NHx] values wouldn't catch some compounds like methylamine, pyridine or anhydrous ammonia

So if anyone has some logic I can program into this thing, that would help a lot.

Thanks in advance for any input

P.S. I suppose another way would be to try and use regex on the name itself, "hydroxide", "amine", "carbonate", etc are bases, and "acid" (and maybe "anhydride") would be considered acids. But I feel like there's a lot of instances where that might miss. Trying to avoid it.

[Edited on 20-2-2025 by SuperOxide]

Texium - 20-2-2025 at 07:14

Everything is an acid and everything is a base. It’s all relative. Where do you draw the line in terms of pKa and pKb?

SuperOxide - 20-2-2025 at 07:57

Quote: Originally posted by Texium  
Everything is an acid and everything is a base. It’s all relative. Where do you draw the line in terms of pKa and pKb?


Yes, technically, you're right. But at the same time would you consider hexane an acid or a base? How about benzene? Would you store them with acids or bases?

This is for categorizing reagents based on their properties, one of which is if its an acid or a base, or neither.

woelen - 20-2-2025 at 08:06

Using SMILES directly is not the tool for determining this. This is like trying to use a hammer for a job, which actually requires a screw driver.

What you could try is first rendering the complete formula, including structural information (e.g. S(=O)(=O)(O)O renders as S(=O)(=O)(OH)(OH). You know that all these groups are attached to a central S-atom. The next step is that when there is a central S-atom, then the H atoms, connected to an O-atom are acidic. This is the case for central halogens atoms, S, Se, Te, P, As. For each of the elements you should have rules like that. Also you should have rules for H-atoms directly attached to other elements, which can be acidic, alkaline, or (nearly) none of them. It will not be easy, but I think it is doable, with a reasonably sized rule base, having a few hundreds of rules, which can be put in a table.

SuperOxide - 20-2-2025 at 08:12

Quote: Originally posted by woelen  
Using SMILES directly is not the tool for determining this. This is like trying to use a hammer for a job, which actually requires a screw driver.

What you could try is first rendering the complete formula, including structural information (e.g. S(=O)(=O)(O)O renders as S(=O)(=O)(OH)(OH). You know that all these groups are attached to a central S-atom. The next step is that when there is a central S-atom, then the H atoms, connected to an O-atom are acidic. This is the case for central halogens atoms, S, Se, Te, P, As. For each of the elements you should have rules like that. Also you should have rules for H-atoms directly attached to other elements, which can be acidic, alkaline, or (nearly) none of them. It will not be easy, but I think it is doable, with a reasonably sized rule base, having a few hundreds of rules, which can be put in a table.


I usually joke "even my projects have projects", I think this is a prime example of how that happens, lol.

chempyre235 - 20-2-2025 at 08:32

You might try USDOT numbers or CAS numbers for determining how to best sort reagents. SMILES would be difficult and would likely only work until you got to a reagent that disobeys traditional rules, like squarate or o-diethynylbenzene.
Quote: Originally posted by SuperOxide  

I usually joke "even my projects have projects", I think this is a prime example of how that happens, lol.

Yeah, somehow I'm always attracted to difficult projects, too. :D You should see my hydrocarbon visualizer spreadsheet!

Attached is the USDOT hazmat database.

Attachment: Hydrocarbon Plotter.xlsx (21kB)
This file has been downloaded 121 times

Attachment: Hazardous Materials Table.pdf (201kB)
This file has been downloaded 1263 times

[Edited on 2/20/2025 by chempyre235]

teodor - 20-2-2025 at 08:42

Hi SuperOxide.

In other thread you mentioned you liked the classification scheme for reagent storage I shared.
So, just to illustrate how to use that with your examples (hexane and benzene).

1. Hexane. Look at the wikipedia "hexane" and look which GHS pictograms (https://en.wikipedia.org/wiki/GHS_hazard_pictograms) it has (In case the bottle has slightly different pictograms I usually follow those the bottle has). They are GHS02, GHS07, GHS08, GHS09 for Hexane in Wikipedia.
GHS02 means "flammable". In this case according to the classification schema you need to check "Hazard statements" (or H-codes which correspond to) "Catches fire spontaneously ..." and "In contact with water releases ...". You can check the codes, for example, here - https://www.msds-europe.com/h-statements . It is convenient to put it on your classification flowchart because on some bottles (as well as in wikipedia) they list only codes. For "Catches fire spontaneously ..." it is H250 and for "In contact with water releases ..." they are H260 and H261.
Hexane has those hazards listed in Wikipedia:
H225 , H302, H305, H315, H336, H361, H373, H411
So, it is not PW group.
Then check "... flammable liquid ..." and "... flammable aerosol ...". These codes are:

H222 – Extremely flammable aerosol
H223 – Flammable aerosol.
H224 – Extremely flammable liquid and vapour.
H225 – Highly flammable liquid and vapour.
H226 – Flammable liquid and vapour.

We have H225 listed for hexane. So it goes to FL (flammable) group. In this case it doesn't matter is it acid or base because flammable storage group has priority over IA/OA/IB the same way as PW (pirophoric and water reactive) has priority over FL. Also, there is no "OB" (organic base group) in the scheme. Also hexane is alkane and extremely inert. The knowledge of compound properties always help.

2. Benzene
GHS02, 06, 07, 08, 09
H225, H302, H304, H305, H315, H319, H340, H350, H372, H410
Goes to the same group FL.

But when you have many organic compounds you can separate them further using "aliphatic", "aromatic" etc. This is not for safety but for convenience.

Regarding your question "what is a base and what is an acid" it is not so simpe. Is CrO3 an acid? Is FeCl3 an acid? Is K2CO3 a base?
The first thing it is always solvent-dependent. For storage practically we consider only the reaction with water because it is water wapors which usually matters. In this case CrO3 could be regarded as and acid because it is anhydride (think what you will get after dissolving it) but K2CO3 will not be regarded as a base (for storage) because it has no GHS05 pictogram (not corrosive). But both are hygroscopic, so use a bottle with a tight stopper, place it in a zip packet and put it into freezer under "General storage" group.

Anhydrous FeCl3 is also hygroscopic and best storage is a freezer. There is a huge group of hygroscopic compounds which release HCl on water contact. So, this is a good way to store FeCl3 in the same plastic box with them becaue HCl will not harm FeCl3 (let say "HCl" group). Put some NaOH or KOH in an open container in the same plastic box. It will adsorb HCl as well as will work as an indicator: you will see when some compound releases it by noticing formation of crystalls of NaCl/KCl.

SuperOxide - 20-2-2025 at 08:48

Quote: Originally posted by chempyre235  
You might try USDOT numbers or CAS numbers for determining how to best sort reagents. SMILES would be difficult and would likely only work until you got to a reagent that disobeys traditional rules, like squarate or o-diethynylbenzene.


Yeah, I'm not at all opposed to using an external source to determine this if that's necessary.

Quote: Originally posted by chempyre235  

Yeah, somehow I'm always attracted to difficult projects, too. :D You should see my hydrocarbon visualizer spreadsheet!

Very nice! Downloaded. I'll check it out when I have some extra time (@ work now)
Quote: Originally posted by chempyre235  
Attached is the USDOT hazmat database.

That looks like a nice list, but I'm trying to determine what group a chemical might go in without having to rely on external lists, since the lists don't include everything.

Fellow SM user teodor shared this pdf with me and it shows how chemicals are determined to be in what group, and I'm trying to see if I can automate that logic:
Attachment: lab_chemical_storage_guide.pdf (458kB)
This file has been downloaded 158 times

I have endpoints I can call to get most of the chemical information (GHS labels, pictograms, precautions, hazard statements, etc). Im not sure if I have one that can be used to determine if its an acid or base though. I would think Pubchems public API would have some details about that, but I don't see it.

Edit: Damn @teodor, you commented literally right as I mentioned you, lol.

[Edited on 20-2-2025 by SuperOxide]

SuperOxide - 20-2-2025 at 09:04

Quote: Originally posted by teodor  
Hi SuperOxide.

In other thread you mentioned you liked the classification scheme for reagent storage I shared.
So, just to illustrate how to use that with your examples (hexane and benzene).

1. Hexane. Look at the wikipedia "hexane" and look which GHS pictograms (https://en.wikipedia.org/wiki/GHS_hazard_pictograms) it has (In case the bottle has slightly different pictograms I usually follow those the bottle has). They are GHS02, GHS07, GHS08, GHS09 for Hexane in Wikipedia.
GHS02 means "flammable". In this case according to the classification schema you need to check "Hazard statements" (or H-codes which correspond to) "Catches fire spontaneously ..." and "In contact with water releases ...". You can check the codes, for example, here - https://www.msds-europe.com/h-statements . It is convenient to put it on your classification flowchart because on some bottles (as well as in wikipedia) they list only codes. For "Catches fire spontaneously ..." it is H250 and for "In contact with water releases ..." they are H260 and H261.
Hexane has those hazards listed in Wikipedia:
H225 , H302, H305, H315, H336, H361, H373, H411
So, it is not PW group.
Then check "... flammable liquid ..." and "... flammable aerosol ...". These codes are:

H222 – Extremely flammable aerosol
H223 – Flammable aerosol.
H224 – Extremely flammable liquid and vapour.
H225 – Highly flammable liquid and vapour.
H226 – Flammable liquid and vapour.

We have H225 listed for hexane. So it goes to FL (flammable) group. In this case it doesn't matter is it acid or base because flammable storage group has priority over IA/OA/IB the same way as PW (pirophoric and water reactive) has priority over FL. Also, there is no "OB" (organic base group) in the scheme. Also hexane is alkane and extremely inert. The knowledge of compound properties always help.

2. Benzene
GHS02, 06, 07, 08, 09
H225, H302, H304, H305, H315, H319, H340, H350, H372, H410
Goes to the same group FL.

But when you have many organic compounds you can separate them further using "aliphatic", "aromatic" etc. This is not for safety but for convenience.

Yes, those ones/groups I'm not concerned about. I was just using solvents as examples of what one wouldn't consider when thinking of acids or bases.


Quote: Originally posted by teodor  

Regarding your question "what is a base and what is an acid" it is not so simpe. Is CrO3 an acid? Is FeCl3 an acid? Is K2CO3 a base?
The first thing it is always solvent-dependent. For storage practically we consider only the reaction with water because it is water wapors which usually matters. In this case CrO3 could be regarded as and acid because it is anhydride (think what you will get after dissolving it) but K2CO3 will not be regarded as a base (for storage) because it has no GHS05 pictogram (not corrosive). But both are hygroscopic, so use a bottle with a tight stopper, place it in a zip packet and put it into freezer under "General storage" group.

Anhydrous FeCl3 is also hygroscopic and best storage is a freezer. There is a huge group of hygroscopic compounds which release HCl on water contact. So, this is a good way to store FeCl3 in the same plastic box with them becaue HCl will not harm FeCl3 (let say "HCl" group). Put some NaOH or KOH in an open container in the same plastic box. It will adsorb HCl as well as will work as an indicator: you will see when some compound releases it by noticing formation of crystalls of NaCl/KCl.

I think I get what you're saying - even compounds under the same group may still require different storage conditions, which I understand. The specific storage conditions can be determined later, but for now it's just the best group to place them with that I'm trying to automate (if possible).

teodor - 20-2-2025 at 10:03

Fellow SM user SuperOxide :), to enjoy a home laboratory we need always pay attention to the fact that the base of the word "laboratory" is a "labor".
Without labor a laboratory is just a storage which never can be organized perfectly by the way.
When you have going several experiments at the same time (which is practically very good if you have space) the storage is always a supplement to your process.
To have a proper storage anyone need experience and understanding what is so important about it.
Most of regulations, as I already said, are inspired by preventing accidents, and this is also important in a home lab but not only this.

The first thing the storage should allow to spend time you have for experiments effectively (and any unnecessary accidents will not). The most important thing for that is to know chemicals. The sorting them and reading about them is also a good thing for that. But putting them into actions is much better. For that you need to organize the space properly. The storage space should be arranged around experimental space. It depends on a type of laboratory also. The storage conditions for perfumery laboratory is different from analytical laboratory or laboratory for organic syntheses. If you have a mix of different activities the storage rules also will be a mix.

So, the speed and safety of the access is the first condition for storage. Think about proper labelling and putting bottles with nasty chemicals in positions where they can be safe in most circumstances you can experience in the lab.
The second is that you need to keep your reagents fresh as much as possible. And your enemies here are poor bottles, wrong labelling, humidity, temperature, sunlight, vapors from other chemicals.
The most harm is from humidity, the next thing are acid vapors. Some gases also can penetrate stoppers. In reality all your reagents are degraded constantly, you need only to slow down this process.

And after your reach your first 2 goals thing about the air in your lab. It must be fresh and without any smells. If the air has constant smell it is no good, you need to improve the storage.

So, if you have a lab where you can do experiments safely, keep your reagents in a good order for a long time and there is no smell in the air - you are doing things right doesn't matter how you sort your chemicals. Because it is more important to understand everything about chemicals and have a practice of usage every of them and when you say "automate" it is not about understanding of that.

[Edited on 20-2-2025 by teodor]

Texium - 20-2-2025 at 13:10

Quote: Originally posted by SuperOxide  
Quote: Originally posted by Texium  
Everything is an acid and everything is a base. It’s all relative. Where do you draw the line in terms of pKa and pKb?


Yes, technically, you're right. But at the same time would you consider hexane an acid or a base? How about benzene? Would you store them with acids or bases?

This is for categorizing reagents based on their properties, one of which is if its an acid or a base, or neither.
Cool, it wasn't clear from your opening post what the end goal was. The context is helpful.

When it comes to storage, in the research labs I've worked in, I've learned that keeping the categories simple and the exceptions as few as possible is best. Inorganic acids and volatile organic acids such as acetic and formic, as well as acetic anhydride, and other corrosive inorganics like thionyl chloride, acetyl chloride, and bromine get stored in the corrosives cabinet. Very reactive anhydrides like mesic and triflic live in a desiccator. But those are the exceptions – other organic acids that are nonvolatile or only mildly acidic go in general storage.

For bases, solid, nonvolatile inorganic bases go in general storage. So do most amines. The exception is the more volatile liquid ones such as triethylamine, pyridine, and piperidine, which go in their own corrosive/flammable bases cabinet.

Large bottles of flammamble liquids go in a flammables cabinet. Anything <250 mL goes in general storage.

At a certain point, separating chemicals into many categories becomes impractical. What do you do with bifunctional compounds, like amino acids? Besides the exceptional cases that I outlined above, where the physical hazards of storing the chemical outweigh the convenience of organization, 90% of the chemicals are in general storage, with inorganics sorted by metal (for salts and metals) and organics sorted by the number of carbons in the molecule.

Precipitates - 20-2-2025 at 21:58

Quote: Originally posted by SuperOxide  

Yes, technically, you're right. But at the same time would you consider hexane an acid or a base? How about benzene? Would you store them with acids or bases?


Would store them separately, in a dedicated area for organic solvents*

*Or at least that's what I should do. The reality is my chemicals are pretty mixed up at the moment.

The lab I was at, which is much better organised than my home lab, stores them separately.

Acids, bases, organic solvents and dry chemicals is probably enough categorisation for me.

[Edited on 21-2-2025 by Precipitates]

SuperOxide - 20-2-2025 at 22:43

Quote: Originally posted by Precipitates  
Quote: Originally posted by SuperOxide  

Yes, technically, you're right. But at the same time would you consider hexane an acid or a base? How about benzene? Would you store them with acids or bases?


Would store them separately, in a dedicated area for organic solvents*

*Or at least that's what I should do. The reality is my chemicals are pretty mixed up at the moment.

Yeah, I realize that. That was more of a rhetorical question in regards to everything being acidic or basic to some degree. I was simply saying in every day use, or for storage, you would never consider an non-polar organic solvents to be either acids or bases.

teodor - 21-2-2025 at 03:59

There could be understandable reasons for different practice of storage compounds in professional and amateur labs.

The first thing, preserving compounds is more important goal for amateurs than for professionals because for amateurs it is not easy to get some of them second time. Investing in a dedicated freezer (household freezer is a good choice, but don't mix chemicals with food) and keeping as much as possible in dry athmosfere (in freezer) has more sence for amateurs. That's why I would pay more attention to the "Hygroscopic" storage class than for "inorganic bases".

The second thing, when we are talking about regulations for professional labs they assume you already have proper ventilation and firefighting equipment. For amateur lab it is also important, so you need to plan the storage, fire prevention and ventilation in connection. That's why we are unable to decide what is the proper way to separate group and store chemicals without any clue what is supposed procedure to control fire or wether our air circulation in places where chemicals are stored is enought to meet the requirements.

The air in a lab should not only have a proper temperature and humidity but also it should leave the place with some speed (measured as lab volumes per hour). This is dependent on the current activity. For most of laboratories the outlet through fume hood is enough for proper circulation but the place of inlets is not less important. Also there should be still ventilation when a fume hood is not working.
Those are complex thing, but I'd like to point out that you unable to apply all the rules from professional lab without considering the storage environment.

For homes without proper ventilation or fire protection design it is wise to store some group of chemicals in garden sheds or just cabinets outside and here you will consider humidity and temperature to decide what should be the group for storage there.

[Edited on 21-2-2025 by teodor]

chornedsnorkack - 21-2-2025 at 14:24

One thing to consider is compatible materials.
For example, materials which have or may give off reactive fluorous vapours should require special handling. HF corrodes glass, and so do some of the volatile fluorides - they need different materials to withstand them.
Glass that withstands HCl fumes also is resistant to HBr, HI and many other volatile acids but not HF. And some metals that are passivated by HF don´t stand HCl.

[Edited on 21-2-2025 by chornedsnorkack]

Texium - 21-2-2025 at 15:13

Quote: Originally posted by teodor  
There could be understandable reasons for different practice of storage compounds in professional and amateur labs.

The first thing, preserving compounds is more important goal for amateurs than for professionals because for amateurs it is not easy to get some of them second time. Investing in a dedicated freezer (household freezer is a good choice, but don't mix chemicals with food) and keeping as much as possible in dry athmosfere (in freezer) has more sence for amateurs. That's why I would pay more attention to the "Hygroscopic" storage class than for "inorganic bases".

The second thing, when we are talking about regulations for professional labs they assume you already have proper ventilation and firefighting equipment. For amateur lab it is also important, so you need to plan the storage, fire prevention and ventilation in connection. That's why we are unable to decide what is the proper way to separate group and store chemicals without any clue what is supposed procedure to control fire or wether our air circulation in places where chemicals are stored is enought to meet the requirements.

The air in a lab should not only have a proper temperature and humidity but also it should leave the place with some speed (measured as lab volumes per hour). This is dependent on the current activity. For most of laboratories the outlet through fume hood is enough for proper circulation but the place of inlets is not less important. Also there should be still ventilation when a fume hood is not working.
Those are complex thing, but I'd like to point out that you unable to apply all the rules from professional lab without considering the storage environment.

For homes without proper ventilation or fire protection design it is wise to store some group of chemicals in garden sheds or just cabinets outside and here you will consider humidity and temperature to decide what should be the group for storage there.
I didn’t mention it, but in the lab I work in we have multiple fridges/freezers for chemicals as well, and desiccator cabinets for compounds that are hygroscopic but fine to store at room temp. Utah is a very dry place though, so many hygroscopic things are fine to keep on a shelf in the open without noticeable degradation. That won’t be the case in other places. I had to store a lot more things in desiccators when I lived in Texas, for instance.

The point about different regulations for professional labs vs homes is a good one though. The room where our general chemicals are stored is built for that purpose, and is well ventilated. I don’t know what the exact airflow rate is though. Even so, the vast majority of chemicals are not particularly volatile nor reactive, so as long as you have a plan for safely storing the most hazardous ones and the ones with particular humidity or temperature needs, the rest should be fine to store together, and more practical too, especially if you have a large number of chemicals. I agree with what you said in your earlier post about how it’s important to store things in a way that makes it easy and practical for you to find things as you are running experiments. Organization is good, but having too many arbitrary categories that aren’t necessary for safety reasons will slow you down and make it more complicated to find things.

teodor - 22-2-2025 at 05:07

Quote: Originally posted by Texium  
Quote: Originally posted by teodor  
There could be understandable reasons for different practice of storage compounds in professional and amateur labs.

The first thing, preserving compounds is more important goal for amateurs than for professionals because for amateurs it is not easy to get some of them second time. Investing in a dedicated freezer (household freezer is a good choice, but don't mix chemicals with food) and keeping as much as possible in dry athmosfere (in freezer) has more sence for amateurs. That's why I would pay more attention to the "Hygroscopic" storage class than for "inorganic bases".

The second thing, when we are talking about regulations for professional labs they assume you already have proper ventilation and firefighting equipment. For amateur lab it is also important, so you need to plan the storage, fire prevention and ventilation in connection. That's why we are unable to decide what is the proper way to separate group and store chemicals without any clue what is supposed procedure to control fire or wether our air circulation in places where chemicals are stored is enought to meet the requirements.

The air in a lab should not only have a proper temperature and humidity but also it should leave the place with some speed (measured as lab volumes per hour). This is dependent on the current activity. For most of laboratories the outlet through fume hood is enough for proper circulation but the place of inlets is not less important. Also there should be still ventilation when a fume hood is not working.
Those are complex thing, but I'd like to point out that you unable to apply all the rules from professional lab without considering the storage environment.

For homes without proper ventilation or fire protection design it is wise to store some group of chemicals in garden sheds or just cabinets outside and here you will consider humidity and temperature to decide what should be the group for storage there.
I didn’t mention it, but in the lab I work in we have multiple fridges/freezers for chemicals as well, and desiccator cabinets for compounds that are hygroscopic but fine to store at room temp. Utah is a very dry place though, so many hygroscopic things are fine to keep on a shelf in the open without noticeable degradation. That won’t be the case in other places. I had to store a lot more things in desiccators when I lived in Texas, for instance.

The point about different regulations for professional labs vs homes is a good one though. The room where our general chemicals are stored is built for that purpose, and is well ventilated. I don’t know what the exact airflow rate is though. Even so, the vast majority of chemicals are not particularly volatile nor reactive, so as long as you have a plan for safely storing the most hazardous ones and the ones with particular humidity or temperature needs, the rest should be fine to store together, and more practical too, especially if you have a large number of chemicals. I agree with what you said in your earlier post about how it’s important to store things in a way that makes it easy and practical for you to find things as you are running experiments. Organization is good, but having too many arbitrary categories that aren’t necessary for safety reasons will slow you down and make it more complicated to find things.


I store chemicals now in a lab itself and in a basement just below the lab. I have a long table with the second table attached perpendicularly. The long table have shelves above and drawers below. The system of storage in this area was formed during my home lab evolution which was started with few chemicals and almost no equipment. Now I have quite some. I would say here I plan to store chemicals only temporarily for ongoing experiments, results and intermediates, so on permanent base it is mostly for equipment. Will see, the evolution is not stopped. Because I can use burners in this area I placed flammable liquids in a shelf not attached to the table. But not in the basement because I don't want accidental buildup on flamable vapors in that area which I visit not too often. And what is even more important, fighting fire in a basement is very dangrous activity because of only one staircase which could be blocked in case of fire.
I have also a big shelf apart from tables for inorganic reagents sorted by some system to find any of them quickly. Also there are small shelves near the center for such groups as analytical reagents, perfumery raw matherials where I keep the most of esters and things synthesized or bought because of smell just to check/recall their smell because I'd like to remember it, so it is in easily accessible zone as well as analytical reagents, stains for microscopy (most of them are presented to me by Adrian known by Adrian's Chemical Laboratory youtube channel, I have constant correspondence with him also regarding building of a new lab, he is doing the same thing now because his old lab doesn't exist anymore), some specialized reagents for biology as a separate group. And also I have a big freezer in the lab filled with plastic boxes. There are 4 groups here: HCl group (acyl and other volatile chlorides etc), Bromine bottles in a separate box, General Storage and Inorganic Bases. In the Netherlands we have very high humidity, so this is more to keep some things in a dry environment.
In the basement I keep volatile acids, not hygroscopic organic reagents sorted by some system, results of experiments sorted by experiment ID, not hygroscopic oxidisers and there is a second freezer with organic acids and oxidizers to separate them from what I store in the first freezer. I plan to put also a table there because I often go to basement to fill some small bottle from a big bottle stored in a basement. The humidity in this area is always above 60% so it limits the chemicals which could be stored there.
There is a small group of chemicals which I keep outside of my lab in a workshop, like phenylacetic acid and diethyl ether.

I have only 2 dessicators and also was keeping something there (when I didn't use them for other purposes) but I would like to know more about the professional practice of usage of dessicator cabinets you mentioned.

[Edited on 22-2-2025 by teodor]

[Edited on 22-2-2025 by teodor]

[Edited on 22-2-2025 by teodor]