7 ms·

Just note that Flouride and Flourine are very different things. Chlorine is also very highly reactive and dangerous but you think nothing of eating table salt.

RC_ITR 5y ago
As with almost all controversial health discussions, everyone loves to talk about elemental chemistry and hates to talk about ionization.
- whatshisface 5y ago
  Yeah, everyone is imagining F2 and CF4, but what we're dealing with is F-, totally different from the other two.
jjoonathan 5y ago
Just look at this video of sodium exploding in water! Now buy my all-natural alternative!
lend000 5y ago
You'll find fluorine atoms in a disproportionate number of poisons, while other halogens are much weaker. It really is an anomalous atom and the comparison to Chlorine is not accurate (which is less electronegative than oxygen). I wondered why we don't use something that can also promote crystallization of hydroxyapatite (primary mineral in surface tooth enamel), and apparently it's because carbonate also promotes plaque crystallization. However, if you go to the dentist regularly, it seems an objectively better personal option. The argument for water fluoridation is a macro-argument that looks good from 10,000 feet, but when you apply nuance, such a policy does not benefit (and probably subtly harms) the vast majority of readership on HN, and is more likely to affect the most impoverished who do not brush their teeth regularly and cannot afford or do not prioritize going to the dentist (which is a surprisingly high percentage of the general public). That isn't to say it's a bad policy, but it certainly isn't black and white.
- jjoonathan 5y ago
  > You'll find fluorine atoms in a disproportionate number of poisons You'll also find carbon in a disproportionate number of poisons. The horror!
  - lend000 5y ago
    I know this is an attempt at humor, but this kind of low quality engagement has no place on HN. Carbon is the backbone of almost all compounds used by life. Feel free to check the ratio of poisons/non-poisons containing Carbon and those containing Fluorine and report back. Carbon is fundamentally different than halogens and really all other nonmetals due to its unique, strong affinity for 4 bonds, its small size, its relative non-electronegativity compared to other common elements in organic compounds (besides hydrogen), and the lack of d orbital complexity. Source: I'm a computational chemist.
- nick__m 5y ago
  Sure fluorine is extremely reactive but once a F is bonded to a C, it's quite hard to dislodge. To remove that bounded F you need a really strong oxidant like ozone. Chlorofluorocarbons were used as propellant in sprays and asthma pump because they didn't react with the active substances. The presence of fluoride in a disproportionate number of poisons (FOOF excluded) is due to the fact that as far as biological binding site are concerned it's almost like a really heavy hydrogen but metabolically it protect that carbon from being the target of an enzyme¹. This enable a toxic molecule that would be quickly metabolized to stay active long enough to do some damage. It's important to note that the presence of a C-F bond doesn't make a molecule inherently toxic, it just make it harder to metabolize when that bond is placed at the target of an enzyme. 1- https://www.sciencedaily.com/releases/2019/03/190305112830.htm https://www.sciencedaily.com/releases/2019/03/190305112830.h...
  - lend000 5y ago
    It's true that F isn't a good leaving group, but that's a double edged sword. By the same token, continuous exposure means that when it is occasionally substituted into organic molecules throughout the body, it will be not easily substituted out. I am curious now what the equilibrium retention point is for typical fluoridation levels.

RC_ITR 5y ago

As with almost all controversial health discussions, everyone loves to talk about elemental chemistry and hates to talk about ionization.

whatshisface 5y ago
Yeah, everyone is imagining F2 and CF4, but what we're dealing with is F-, totally different from the other two.

jjoonathan 5y ago

Just look at this video of sodium exploding in water! Now buy my all-natural alternative!

lend000 5y ago

You'll find fluorine atoms in a disproportionate number of poisons, while other halogens are much weaker. It really is an anomalous atom and the comparison to Chlorine is not accurate (which is less electronegative than oxygen). I wondered why we don't use something that can also promote crystallization of hydroxyapatite (primary mineral in surface tooth enamel), and apparently it's because carbonate also promotes plaque crystallization. However, if you go to the dentist regularly, it seems an objectively better personal option. The argument for water fluoridation is a macro-argument that looks good from 10,000 feet, but when you apply nuance, such a policy does not benefit (and probably subtly harms) the vast majority of readership on HN, and is more likely to affect the most impoverished who do not brush their teeth regularly and cannot afford or do not prioritize going to the dentist (which is a surprisingly high percentage of the general public). That isn't to say it's a bad policy, but it certainly isn't black and white.

jjoonathan 5y ago
> You'll find fluorine atoms in a disproportionate number of poisons You'll also find carbon in a disproportionate number of poisons. The horror!
- lend000 5y ago
  I know this is an attempt at humor, but this kind of low quality engagement has no place on HN. Carbon is the backbone of almost all compounds used by life. Feel free to check the ratio of poisons/non-poisons containing Carbon and those containing Fluorine and report back. Carbon is fundamentally different than halogens and really all other nonmetals due to its unique, strong affinity for 4 bonds, its small size, its relative non-electronegativity compared to other common elements in organic compounds (besides hydrogen), and the lack of d orbital complexity. Source: I'm a computational chemist.
nick__m 5y ago
Sure fluorine is extremely reactive but once a F is bonded to a C, it's quite hard to dislodge. To remove that bounded F you need a really strong oxidant like ozone. Chlorofluorocarbons were used as propellant in sprays and asthma pump because they didn't react with the active substances. The presence of fluoride in a disproportionate number of poisons (FOOF excluded) is due to the fact that as far as biological binding site are concerned it's almost like a really heavy hydrogen but metabolically it protect that carbon from being the target of an enzyme¹. This enable a toxic molecule that would be quickly metabolized to stay active long enough to do some damage. It's important to note that the presence of a C-F bond doesn't make a molecule inherently toxic, it just make it harder to metabolize when that bond is placed at the target of an enzyme. 1- https://www.sciencedaily.com/releases/2019/03/190305112830.htm https://www.sciencedaily.com/releases/2019/03/190305112830.h...
- lend000 5y ago
  It's true that F isn't a good leaving group, but that's a double edged sword. By the same token, continuous exposure means that when it is occasionally substituted into organic molecules throughout the body, it will be not easily substituted out. I am curious now what the equilibrium retention point is for typical fluoridation levels.