# What is the name of As_2S_3?

Jan 2, 2018

This is arsenic trisulfide, a bright yellow solid insoluble in water.

Jan 2, 2018

The name is diarsenic trisulfide.

#### Explanation:

${\text{As"_2"S}}_{3}$ is a binary molecular compound : It consists of only two elements and contains no ions.

The rules for naming the compound are:

1. Write the names of the elements in the same order as in the compound.

This gives the name arsenic sulfur.

2. Replace the name of the second element with its root followed by the suffix -ide.

The root of $\text{sulf}$ur is $\text{sulf-}$.

This gives the name arsenic sulfide.

3 Indicate the numbers of each atom by a multiplying prefix

The multiplying prefix for two is $\mathrm{di} \text{-}$, and the multiplying prefix for three is $t r i \text{-}$.

Thus, the name of ${\text{As"_2"S}}_{3}$ becomes $\boldsymbol{\text{diarsenic trisulfide}}$.