chemtool: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/chemtool - from package: chemtool

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/chemtool - from package: chemtool

You may install the required package with command apt-get install {package}

Error in other languages:
chemtool: bevel nie gevind nie
chemtool: comandă negăsită
chemtool: comando não encontrado
chemtool: commande introuvable
chemtool: command not found
chemtool: käsku ei ole
chemtool: không tìm thấy lệnh
chemtool: komanda nerasta
chemtool: Kommando nicht gefunden.
chemtool: kommandot finns inte
chemtool: komut yok
chemtool: nie znaleziono polecenia
chemtool: níor aimsíodh an t-ordú
chemtool: no se encontró la orden
chemtool: no s'ha trobat l'ordre
chemtool: opdracht niet gevonden
chemtool: parancs nem található
chemtool: perintah tidak ditemukan
chemtool: príkaz nenájdený
chemtool: příkaz nenalezen
chemtool: команда не найдена
chemtool: командата не е открита
chemtool: 命令找不到
chemtool: コマンドが見つかりません