xdrawchem: 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 Debian possible default full paths are:

/usr/bin/xdrawchem - from package: xdrawchem

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

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