What is the Difference Between Arsenic and Cyanide

The key difference between arsenic and cyanide is that arsenic is a poisonous chemical element that occurs as a metalloid material, whereas cyanide is a group of poisonous chemical compounds consisting of a cyanide functional group.

Arsenic is a chemical element having the atomic number 33 and the chemical symbol As. Cyanide is any chemical compound having a cyano (C≡N) group.

CONTENTS

1. Overview and Key Difference
2. What is Arsenic 
3. What is Cyanide 
4. Similarities – Arsenic and Cyanide
5. Arsenic vs Cyanide in Tabular Form
6. Summary – Arsenic vs Cyanide 

What is Arsenic?

Arsenic can be described as a chemical element having the atomic number 33 and the chemical symbol As. This chemical element occurs as a grey-coloured metalloid. Moreover, arsenic naturally occurs in different minerals; e.g. in combination with other elements such as sulfur and metals. However, we can find arsenic as pure elemental crystals as well. Furthermore, there are several different allotropes of arsenic, but the isotope with the metallic appearance is mostly used in industrial applications. Arsenic occurs in nature as a monoisotopic metalloid. That means it has a single stable isotope.

In addition, arsenic is a p-block element. It is located in group 15 and period 4 of the periodic table. The electron configuration of this metalloid is [Ar]3d104s24p3. Furthermore, this metalloid is in a solid-state at room temperature. Upon heating, it can undergo sublimation.

There are three common allotropic forms of arsenic: grey, yellow, and black arsenic. The most common and useful form is grey arsenic. The crystal structure of arsenic is rhombohedral. When considering its magnetic properties, arsenic is diamagnetic. Grey arsenic is a brittle material due to the weak chemical bonding between the layers of the allotrope.

What is Cyanide?

Cyanide can be categorized as any chemical compound having a cyano (C≡N) group. The cyano group has a carbon atom and a nitrogen atom, which are linked via a triple bond. Thus, the term cyanide may refer to any organic or inorganic compound containing a cyano group. In contrast, the term nitrile refers to any organic compound having a cyano group.

Usually, in inorganic cyanides, the cyano group is present as an anion; for example, sodium cyanide and potassium cyanide. Moreover, these cyanides are highly toxic. Hydrogen cyanide or HCN is a highly volatile and highly toxic substance. In nitriles, the cyano group is attached to a covalent bond to the rest of the molecule (not as an ion). A common example would be acetonitrile.

Moreover, cyanides are produced by many bacteria, fungi, and algae species. Cyanide is also a common component in many plants. Furthermore, these compounds form as a byproduct of combustion in an oxygen-deficient environment.

When considering the applications of cyanides, these compounds are useful in mining silver and gold because cyanides help to dissolve these metals. Furthermore, cyanides are important as precursors for the organic synthesis processes, e.g., the production of nylon. Besides, there are applications of cyanide in the field of medicine and pest control.

What are the Similarities Between Arsenic and Cyanide?

• Both are highly toxic/poisonous substances.
• Arsenic rivals cyanide in both lethality and infamy.

What is the Difference Between Arsenic and Cyanide?

Both arsenic and cyanide are poisonous chemical materials. The key difference between arsenic and cyanide is that arsenic is a poisonous chemical element that occurs as a metalloid, whereas cyanide is a group of poisonous chemical compounds consisting of a cyanide functional group.

Below is a summary of the difference between arsenic and cyanide in tabular form for side by side comparison.

Summary – Arsenic vs Cyanide

Arsenic is a chemical element having the atomic number 33 and the chemical symbol As. Cyanide is any chemical compound having a cyano (C≡N) group. The key difference between arsenic and cyanide is that arsenic is a poisonous chemical element that occurs as a metalloid, whereas cyanide is a group of poisonous chemical compounds consisting of a cyanide functional group.

Reference:

1. Venosa, Ali. “How 4 Lethal Poisons Actually Kill You.” Medical Daily, 27 Apr. 2016.

Image Courtesy:

1. “Arsenic Poisoning” By Anita Ghosh/REACH – (CC BY 2.0) via Commons Wikimedia
2. “Acyl cyanide synthesis” By Mephisto spa – Own work (CC BY-SA 4.0) via Commons Wikimedia