def get_xyz(rd_mol):
    """
    Convert an RDKit mol to an xyz (atomic number + coordinates).
    Args:
        rd_mol (rdkit.Chem.rdchem.Mol): RDKit mol
    Returns:
        xyz (list): atomic number + coordinates 
    """

    atoms = rd_mol.GetAtoms()

    atom_nums = []
    for atom in atoms:
        atom_nums.append(atom.GetAtomicNum())

    # each conformer is a separate rdkit mol object, so each
    # mol has only one conformer

    rd_conf = rd_mol.GetConformers()[0]
    positions = rd_conf.GetPositions()

    xyz = []
    for atom_num, position in zip(atom_nums, positions):
        xyz.append([atom_num, *position])

    return xyz