Rhodium Chemical Properties (23 Facts You Should Know)

Every element has some chemical characteristics that make it helpful to society in a variety of ways. Let us examine Rhodium facts in more detail.

Rhodium(Rh) is a reflective metal that is strong, silvery, and long-lasting. Even when heated, rhodium metal does not typically produce an oxide. Compared to platinum, rhodium has a lesser density and a more excellent melting point. 

Let us explore Rhodium’s chemical properties in detail, including its atomic symbol, electronic configuration, melting point, ionisation energy, and isotopes.

Rhodium symbol

The chemical symbol is used to briefly describe a chemical element. Let us identify the Rhodium symbol.

Rhodium is represented by the symbol of “Rh” in the periodic table.

Rhodium group in periodic table

According to the periodic table, a group is a column of elements. Let us predict the Rhodium group.

Rhodium (Rh) is in the 9^th group in the periodic table. Depending on how many electrons are present in the final electronic shell, the group is divided. Rh belongs to group 9 in the table because its outermost shell has 9 electrons.

Rhodium period in periodic table

In the periodic table, a period is a row that contains a specific quantity of chemical elements. Let us look at the Rhodium period.

Rhodium belongs to the 5^th period of the periodic table. 

Rhodium block in periodic table

The element that makes up the block has similar physical and chemical properties. Let us check the Rhodium block.

Rhodium is considered a transition element in the d-block. This is because the d electronic shell is the element’s last shell, also known as the valence shell.

Rhodium atomic number

The periodic table’s “block” represents a group of elements with related chemical and physical characteristics. Let us discuss the Rhodium block.

Rhodium is a natural element with an atomic number of 45. It consists of 45 protons and 45 electrons.

Rhodium atomic Weight

An element’s average weight compared to all of its isotopes and their proportionate abundances are known as its atomic weight. Let us talk about Rhodium atomic weight.

The atomic weight of rhodium is 102.905 g/mol.

Rhodium Electronegativity according to Pauling

Electronegativity is the ability of an atom to draw the bonding electron pairs of other atoms.  Let us take a look at the Rhodium electronegativity value.

Rhodium has a Pauling electronegativity value of 2.28, similar to some other 9^th group elements.

Rhodium atomic Density

The atomic density of an element is the number of atoms in that element per unit volume. Let us talk about Rhodium atomic density.

The density of Rhodium at room temperature should be 12.41 g/cm³. This indicates that a total density of 12.41 Rh can be found in 1cm³ of Rh. But when it melts and reaches its melting point, it turns into a liquid, the density is 10.7 g/cm³.

Rhodium melting point

A substance’s melting point is the temperature at which it melts. Let us check out the Rhodium melting point.

Rhodium has a melting point of 2237 K ​(1964 °C, ​3567 °F).

Rhodium boiling point

In its liquid state, a substance starts to boil at its boiling point. Let us determine the Rhodium boiling point. 

Rhodium has a boiling point of 3968 K ​(3695 °C, ​6683 °F).

Rhodium Vanderwaals radius

A Vander Waals radius is the distance between two atoms of an element held together by their nuclei’s attraction. Let us examine the Vander Waals radius of the Rhodium.

The van der Waals radius of Rhodium is 2.32 Å (180pm (1pm=1*10^{‑12 m})). It relates to the size of a hypothetical hard sphere that was produced by an element’s final electronic shell.

Rhodium ionic radius

The distance between an ion’s ionic nucleus and its last orbital’s valence shell electrons is known as the ionic radius. Let us examine Rhodium ionic radius. 

The ionic radius for rhodium in its (+3) oxidation state is 0.67. The numerous coordination centres and ionic radii of rhodium are displayed in the table below:

Rhodium Ion (Rhn+ )	Coordinating Structure	Ionic Radius (1pm=1*10‑12 m)
Rh(III)	6-coordinate, octahedral	80.5pm
Rh(IV)	6-coordinate, octahedral	75pm
Rh(V)	6-coordinate, octahedral	69pm

Rhodium isotopes

In isotopes, the number of protons remains the same but the number of neutrons changes. Let us count the isotopes that Rhodium has.

Rhodium has 30 radioisotopes ranging in atomic weight from 88.949 u (89Rh) to 121.943 u. (122Rh). It only contains one isotope(103-Rh) that occurs naturally. Beta emission is the main form of decay after the single stable isotope, 103Rh, whereas electron capture is the main mode before it. 

Nuclide of Rhodium	Mass of Isotopes	Half-life	Decay mode
101Rh	101	3.3y	EC
101Rhm	101	4.35d	EC, IT
102Rh	102	~2.9y	EC
102Rhm	102	207d	EC, β–, β+
103Rh	103	Stable	Stable
105Rh	105	35.36h	β–
105Rhm	105	40s	IT
106Rh	106	29.9s	β–

Rhodium electronic shell

Each of the electronic shells that envelop the nucleus has a specific number of electrons. Let us examine Rhodium electronic shell.

Rhodium has an electronic shell structure of 2, 8, 18, 16, and 1, around its nucleus, which has the s, p, and d orbitals. 

Rhodium electron configurations

The arrangement of an element’s electrons within its orbitals is known as its electron configuration. Let us examine the electron configurations of Rhodium.

Rhodium has the following electron configurations: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁸ 5s¹ or [Kr] 4d⁸ 5s¹.

Rhodium energy of first ionisation

An outer shell electron must be removed from the last orbital to release the first ionisation energy. Let us look at the 1^st ionisation energy of Rhodium.

Rhodium requires 719.7  kJ/mol of energy for removing the first electrons from the 4s orbitals([Kr] 4d⁸ 5s¹; Rh→Rh¹⁺) or from the last subshell.

Rhodium energy of second ionisation

The second I.E. refers to the force required to free an electron from a positively charged substance. Let us check the Rhodium 2^nd ionisation energy.

The second ionisation energy of Rhodium is 1740 kJ/mol. Since Rh would be able to maintain stability without the second electron, removing it would be easier: ([Kr] 4d⁸; Rh¹⁺→Rh²⁺).

Rhodium energy of third ionisation

Two electrons that have a +2 charge are removed from the outermost shell of an atom orbital to produce a third I.E. Let us figure out Rhodium’s 3^rd ionisation energy.

The third ionisation energy of Rhodium is 2997 kJ/mol. This energy is required to remove the third electron from the outermost ([Kr] 4d⁷; Rh²⁺→Rh³⁺) orbitals. Because a third electron must be removed from the configuration of Rh²⁺, the third ionisation energy is considerable.

Rhodium oxidation states

Depending on their oxidation state, atoms in chemical complexes can undergo oxidation to various degrees. Let us check the oxidation states of Rhodium.

Rhodium exists in a variety of oxidation states, such as −3, −1, 0, +1,+2, +3, +4, +5, +6, +7. Depending on its level of oxidation, Rh can be an oxide that is amphoteric. The oxidation state +3 is the most stable for Rh. 

The oxidation state of different Rh molecules are shown in the following table:

Oxidation States of Rh ion	Molecule
+2	Rh2(O2CCH3)4
+3	RhCl3, Rh2O3
+4	RhO2
+5	RhF5, Sr3LiRhO6

Rhodium CAS number

The CAS number is one particular form of the number, which is a distinctive identifying number issued globally. Let us look for the CAS number for Rhodium.

The CAS number of the Rhodium molecule is 7440-16-6.

Rhodium ChemSpider ID

Database of free chemical structures, their properties, and related information are easily accessible through ChemSpider. Let us check Rhodium Chemspider ID.

Rhodium Chem Spider ID is 22389. ChemSpider database for information on Rhodium using this ID gives information.

Rhodium chemical classification 

The elements are categorised in the periodic table according to their chemical characteristics. Let us look at the chemical classification of Rhodium.

1. Rhodium is produced in commercial quantities as a by-product of the refining of copper and nickel.
2. Wilkinson’s catalyst chlorotris (triphenylphosphine) rhodium is the most well-known rhodium-halogen compound (I). 
3. Platinum alloys that contain rhodium are tougher than pure platinum and lose weight at high temperatures even more slowly. 

Rhodium state at room temperature

In general, room temperature should be between 20 and 25 °C for comfort. Let us examine Rhodium at its room temperature.

Rhodium is solid at its standard or room temperature(298K). This is due to its high melting and boiling point.

Is Rhodium paramagnetic?

An unpaired electron is what makes a material paramagnetic. Let us check the Rhodium paramagnetic property.

The Rhodium metal is paramagnetic because the valence electrons in rhodium are not grouped in a certain order or have a preference for any one direction of spin. Rh contains 9 unpaired electrons

Conclusion

Rhodium is added to platinum in modest amounts to produce these alloys. High density (12.4 g/cm3; nearly as heavy as osmium, the element with the highest density); tarnishes extremely slowly at room temperature; does not tarnish in the air until heated to roughly 500 °C.