Difference Between Fluorine and Fluoride

Main Difference – Fluorine vs Fluoride

Fluorine is a chemical element that belongs to the group of halogens. It is the lightest halogen. Fluoride is an anion formed from fluorine. Fluorine is often found in the form of fluoride anion in compounds. It has been found that fluorine is the 13^th most common chemical element in the earth’s crust. Most industrially significant minerals are fluorite, fluorapatite, and cryolite. When considering the chemical properties of fluorine and fluoride, they show differences in their atomic structure and chemical behavior. The main difference between fluorine and fluoride is their number of electrons; the number of electrons in fluorine is 9 whereas the number of electrons in fluoride is 10.

Key Areas Covered

1. What is Fluorine
      – Definition, Properties, Reactions, Applications
2. What is Fluoride
      – Definition, Properties, Reactions, Applications
3. What is the Relationship Between Fluorine and Fluoride
      – Fluorine and Fluoride
4. What is the Difference Between Fluorine and Fluoride
      – Comparison of Key Differences

Key Terms: Anion, Base, Cryolite, Fluorapatite, Fluoride, Fluorine, Fluorite, Halogens

What is Fluorine

Fluorine is a chemical element that is represented by the symbol F. Fluorine is positioned in the group 7 of the periodic table of elements. Therefore, fluorine belongs to the p block where non-metals exist. The atomic number of this element is 9. The electron configuration can be given as 1s²2s²2p⁵. Since it has 5 electrons in the p sub-shell, there is an unpaired electron in one p orbital. Therefore, fluorine can easily make its anion by obtaining one electron in order to become stable by obtaining the noble gas electron configuration (of Neon). Moreover, fluorine is the most electronegative element that has been discovered so far. (The value of electronegativity is 4.0).

It has been found that fluorine is the thirteenth most abundant chemical element in the earth’s crust. In standard temperature and pressure, fluorine exists as a diatomic gas. It can be given by the molecular formula, F₂. When it is pure, fluorine gas appears as a pale yellow colored gas. It has a characteristic (pungent) odor. It is a highly reactive gas. It can attack metals very quickly.

Fluorine has only one naturally occurring isotope: ¹⁹F isotope. This isotope has 9 protons and 10 neutrons in its nucleus. It is exceptionally attractive to magnetic fields. Fluorine is commonly found as a component in minerals. The most common and industrially useful minerals include fluorite, fluorapatite, and cryolite. In fluorite, fluorine is in combination with Calcium. The molecular formula of fluorite is CaF₂. It is the main source of fluorine among other forms of minerals.

Figure 1: A piece of Fluorite

Reactions

• Fluorine reacts with hydrogen gas explosively.

                     H_2(g)    +     F_2(g)        →          2HF_(g)

• Fluorine gas can react with water forming HF gas and oxygen gas.

                     2H₂O_(l)    +     2F_2(g)        →          4HF_(g)    +     O_2(g)

• Fluorine can easily be reduced to the only oxidation state it can have: -1 oxidation state. Therefore, fluorine acts as a strong oxidizing agent by reducing itself.

                     F_2(g)   +     2KClO_3(aq)    +    H₂O_(l)        →      2HF_(g)    +    KClO_4(aq)

• Since fluorine is very reactive, it can even react with noble gases such as Xenon (Xe).

                      Xe_(g)      +      F_2(g)        →       XeF_2(g)

Due to its high electronegativity, fluorine forms polar covalent bonds or ionic bonds. In covalent bonding, fluorine can have only single bonds.

The applications of fluorine include polymer and plastic production, rocket fuels, air conditioning, etc.

What is Fluoride

Fluoride is an anion formed from the chemical element fluorine. It is the reduced form of fluorine. Fluoride is given the symbol F^–. The electron configuration of fluoride is 1s²2s²2p⁶. It is similar to the electron configuration of Neon (Ne), which is a stable electron configuration.

Fluoride cannot be further reduced. The oxidation state of fluoride is -1. It can only be oxidized into fluorine where the oxidation state is zero. Fluoride has a negative electrical charge because fluoride is formed from fluorine. Fluorine has 9 protons and 9 electrons. Fluorine is formed when one electron is added to fluorine; there aren’t a sufficient number of protons (positive charges) to neutralize the charge of the extra electron. Therefore, the overall atom gets a negative charge, forming an anion.

Sometimes, the term fluoride is also used to name compounds composed of fluoride anions; for example, sodium fluoride, calcium fluoride, etc. In some complex compounds, fluoride act as a bridging ligand between two atoms (Most of the times, two metals). Often, fluoride is found as an anion in ionic compounds. For example, metal halides are more ionic than that of other halogens.

Figure 02: Fluoride act as a bridging ligand for metal complexes. In the above image, -M- is the metal atom and -F- is the fluoride.

Reactions

Fluoride can act as a base. In aqueous solutions, fluoride can combine with a proton to form HF, which is a weak acid. It is the conjugated acid of fluoride.

F^–_(aq)   +    H⁺_(aq)      →     HF_(aq)

The basicity of fluoride anion can be given as below. The reaction between fluoride anion and water molecule forms HF and OH^– ions.

F^–_(aq)    +    H₂O_(l)    →   HF_(aq)  +    OH^–_(aq)

Applications

HF (Hydrofluoric acid) and fluoride salts are used as fluoride sources in the industry. They are mainly used in the production of fluorocarbon material. Apart from that, it used in biochemical assays as an inhibiting agent for the activity of phosphatases.

Relationship Between Fluorine and Fluoride

Fluoride is the anion made from fluorine. Fluoride is the reduced from of fluorine. Fluorine is found in compounds mainly in the form of fluoride.

Difference Between Fluorine and Fluoride

Definition

Fluorine: Fluorine is a chemical element that is represented by the symbol F.

Fluoride: Fluoride is an anion formed from the chemical element fluorine.

Electrical Charge

Fluorine: Fluorine is neutrally charged.

Fluoride: Fluoride is negatively charged.

Number of Electrons

Fluorine: Fluorine has 9 electrons.

Fluoride: Fluoride has 10 electrons.

Electron Configuration

Fluorine: The electron configuration of fluorine is1s²2s²2p⁵.

Fluoride: The electron configuration of fluoride is1s²2s²2p⁶.

Oxidation State

Fluorine: Fluorine is in zero oxidation state.

Fluoride: Fluoride is in -1 oxidation state.

Radius

Fluorine: The atomic radius of fluorine is about 147 pm.

Fluoride: The ionic radius of fluoride is about 133 pm.

Conclusion

Fluorine is found as a component of minerals. Fluorite is the major source of fluorine. This is the difference between fluorine and fluoride. Fluorine is found in the form of fluoride in most fluorine containing compounds. If not, fluorine can be found in its gaseous phase as diatomic molecules.

References:

1. Helmenstine, Anne Marie. “What Is Fluoride?” ThoughtCo. N.p., n.d. Web. Available here. 31 July 2017.
2. “Fluorine.” Wikipedia. Wikimedia Foundation, 28 July 2017. Web. Available here. 31 July 2017. 

Image Courtesy:

1. “Fluorite-270246” By Rob Lavinsky, iRocks.com – (CC BY-SA 3.0) via Commons Wikimedia