van_der_waals_radius
====================

Van der Waals radius of atom `C`, atom `N` , atom `O` and atom `S` .

+-----+-------+
| key | value |
+=====+=======+
| C   | 1.7   |
+-----+-------+
| N   | 1.55  |
+-----+-------+
| O   | 1.52  |
+-----+-------+
| S   | 1.8   |
+-----+-------+