# What units are "GM"? This can't mean gram.... **URL:** \ **Category:** Factual Questions\ **Created:** [October 25, 2010, 1:54am UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234 "2010-10-25T01:54:06Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 25, 2010, 8:49pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/21 "2010-10-25T20:49:43Z")
> [@Sailboat](#): > > I’ve worked with various engineers and technical people for years and am used to seeing their half-hearted approximations. They’re not very precise with their unit notation, which leads to [occasional consequences](http://en.wikipedia.org/wiki/Mars_Climate_Orbiter). Interesting that they refer to “US customary units.” I’m American and have always heard that system called “English units.” ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [October 25, 2010, 8:54pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/22 "2010-10-25T20:54:22Z")
> [@CookingWithGas](#): > > Interesting that they refer to “US customary units.” I’m American and have always heard that system called “English units.” The US Customary system [is different than the Imperial system](http://en.wikipedia.org/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems). The old [English system](http://en.wikipedia.org/wiki/English_unit) has not been used in England since the early 1800s. Yes, you folks may casually refer to the US system as the “English” system, but after losing a few planes and space probes due to measurement errors, you can be sure that relevent authorities are being Very. Precise. about their unit names. ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [October 27, 2010, 4:52pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/23 "2010-10-27T16:52:46Z")
> [@Mogle](#): > > [nitpick] > A gigameter would be Gm, GM is strictly speaking nonsense since there isn’t any unit(at least that I’m aware of) that has the symbol “M”. > [/nitpick] Capital M is used to denote a solution of 1 mole per litre. So obviously they’re selling a solution of this chemical with a concentration of 600 gigamoles per litre. ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [October 27, 2010, 5:03pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/24 "2010-10-27T17:03:59Z")
> [@MikeS](#): > > Capital M is used to denote a solution of 1 mole per litre. So obviously they’re selling a solution of this chemical with a concentration of 600 gigamoles per litre. Sweet! $600 sounds like a great deal for a chunk of neutronium. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [October 27, 2010, 5:10pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/25 "2010-10-27T17:10:14Z")
> [@Sunspace](#): > > The US Customary system [is different than the Imperial system](http://en.wikipedia.org/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems). Something you’d come to realize if you’re a beer drinker. Bigger pints across the pond! ---
**Author:** ![Mogle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mogle/32/12021_2.png) [@Mogle](https://boards.straightdope.com/u/Mogle)\ **Post date:** [October 27, 2010, 5:15pm UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/26 "2010-10-27T17:15:00Z")
> [@MikeS](#): > > Capital M is used to denote a solution of 1 mole per litre. So obviously they’re selling a solution of this chemical with a concentration of 600 gigamoles per litre. Learn something new every day I guess. But I will note that the official SI unit for concentration is mol/m[sup]3[/sup] with the symbol “c”, which is why I couldn’t find anything with “M” as the symbol. ---
**Author:** ![GameHat](https://avatars.discourse-cdn.com/v4/letter/g/ed655f/32.png) [@GameHat](https://boards.straightdope.com/u/GameHat)\ **Post date:** [October 28, 2010, 4:02am UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/27 "2010-10-28T04:02:41Z")
> [@Jorge\_Burrito](#): > > Yep, gm means gram. Just did a quick check on Sigma-Aldrich and it is a whole lot cheaper there (~$125/25 g). You might check VWR and Alfa-Aesar as well, which are the other big chemical suppliers to see what their prices are like. > > Depending on what precursors are available and their costs, complex chemicals can be time consuming and expensive to make. This is part of the reason some pharmaceuticals cost so much. Sigma-Aldrich probably won’t sell to you unless you have an account. Something about not wanting laymen buying chemicals. 😃 VWR - I’ve bought blind, but it’s always been lab supplies, never chemicals. Never tried buying chemicals from them. Alfa-Aesar - no experience. I have corporate profiles with SA and VWR. My experience has been that chemical supply companies will not sell to you without a corporate account. ---
**Author:** ![GameHat](https://avatars.discourse-cdn.com/v4/letter/g/ed655f/32.png) [@GameHat](https://boards.straightdope.com/u/GameHat)\ **Post date:** [October 28, 2010, 4:14am UTC](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234/28 "2010-10-28T04:14:08Z")
> [@GameHat](#): > > Sigma-Aldrich probably won’t sell to you unless you have an account. Something about not wanting laymen buying chemicals. I do buy chemicals from them, but always from a R&D standpoint. Their website sucks - you have to look up a chemical, then call them, then prove you’re a legitimate buyer (read: established chemical company), then prove you have an account. Only then will they let you order. And SA is never for industrial sized orders, always for R&D. You can get a few hundred grams of nearly everything but nothing on an industrial scale. [Previous page](https://boards.straightdope.com/t/what-units-are-gm-this-cant-mean-gram/558234.md?page=1)