What is the commonality between the antibiotic arsphenamine and azodye ?

Explanation

To answer the question about the commonality between the antibiotic arsphenamine and azodye, we can break it down into the following steps:

### Step 1: Identify the Compounds
- **Arsphenamine**: Also known as Salvarsan, it is a synthetic organic compound that contains arsenic. It was historically used to treat syphilis.
- **Azodye**: These are synthetic dyes that contain an azo group (-N=N-), which is a nitrogen-nitrogen double bond linkage.

### Step 2: Analyze the Chemical Structure
- **Arsphenamine**: It contains arsenic and is characterized by its arsenic double bond linkages.
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