Difference Between Ruthenium and Rhodium

The key difference between ruthenium and rhodium is that ruthenium contains seven electrons in the outermost d electron shell whereas rhodium contains eight electrons in the outermost d electron shell.

Both ruthenium and rhodium are chemical elements in period 5 of the periodic table. But they have different atomic numbers; therefore, these chemical elements have different chemical and physical properties as described below.

1. Overview and Key Difference
2. What is Ruthenium
3. What is Rhodium
4. Side by Side Comparison – Ruthenium vs Rhodium in Tabular Form
5. Summary

What is Ruthenium?

Ruthenium is a chemical element having the atomic number 44. The chemical symbol for ruthenium is Ru, and it is a rare transition metal. We can find ruthenium in group 8 and period 5 of the periodic table of elements. Therefore, it is a d block element, and the electronic configuration of this element is [Kr]4d⁷5s¹. At room temperature and pressure, this chemical element occurs in the solid state and it has a very high melting point (about 2300 Celsius) and a very high boiling point (about 4400 Celsius). The most common and stable oxidation states of ruthenium are +3 and +4. It can form a mildly acidic oxide.

Ruthenium naturally occurs in its primordial state. This solid substance appears as a polyvalent hard white metal. The crystal structure of the solid ruthenium is a hexagonal close-packed structure. Moreover, ruthenium contains unpaired electrons, which makes it paramagnetic. In addition to that, ruthenium has only one electron in the outermost electron shell whereas all other group 8 elements contain two electrons. This is a unique feature of ruthenium.

What is Rhodium?

Rhodium is a chemical element having the atomic number 45. The chemical symbol of this element is Rh. It is a rare transition metal that is in group 9 and period 5 of the periodic table of elements. Rhodium appears as a silvery-white metal. It is a hard metal that is corrosion-resistant and chemically inert. Therefore, we can classify it as a noble metal. There is only one naturally occurring isotope of rhodium (Rh-103). We can find this metal naturally as a free metal due to its inert nature. Sometimes it occurs as an alloy with similar metals, and it rarely occurs as a chemical compound in minerals. E.g. bowieite. The most common oxidation state of rhodium is +3. It can form amphoteric oxides.

When considering the natural occurrence of rhodium, it is primordial, and in its solid-state, rhodium has a face-centered cubic crystal structure. This metal is paramagnetic because it has unpaired electrons. The melting point and boiling point are very high (about 1900 and 3600 Celsius, respectively).

Rhodium is a hard metal having a high reflectance. Normally, it does not form oxides even upon heating. It can absorb oxygen only at the letting point of the metal. Upon solidification, this absorbed oxygen is completely released. Most acids cannot attack rhodium metal. E.g. insoluble in nitric acid.

What is the Difference Between Ruthenium and Rhodium?

Ruthenium is a chemical element having the atomic number 44 while rhodium is a chemical element having the atomic number 45. Both are period 5 elements. The key difference between ruthenium and rhodium is that ruthenium contains seven electrons in the outermost d electron shell whereas rhodium contains eight electrons in the outermost d electron shell.

Below table presents a detailed comparison of both elements to discern the difference between ruthenium and rhodium.

Summary – Ruthenium vs Rhodium

Both ruthenium and rhodium are in the same period in the periodic table of elements, but they are in different groups because they have different atomic numbers. The key difference between ruthenium and rhodium is that ruthenium contains seven electrons in the outermost d electron shell whereas rhodium contains eight electrons in the outermost d electron shell.

Reference:

1. Pedersen, Traci. “Facts About Rhodium.” LiveScience, Purch, 13 Mar. 2018, Available here.

Image Courtesy:

1. “Ruthenium a half bar” By Alchemist-hp (talk) (www.pse-mendelejew.de) – Own work, FAL) via Commons Wikimedia

2. “Rhodium powder pressed melted” By Alchemist-hp (talk) www.pse-mendelejew.dederivative work: Purpy Pupple (talk) – Own work (CC BY-SA 3.0 de) via Commons Wikimedia