avogadro software package provides Molecular Graphics and Modelling System, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install avogadro
avogadro is installed in your system.
Make ensure the avogadro package were installed using the commands given below,
$ sudo dpkg-query -l | grep avogadro *
You will get with avogadro package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Science |
| Package | avogadro |
| Version | 1.1.1-0ubuntu7 |
| Description | Molecular Graphics and Modelling System |
| Sub Section | Science |