Units of measurement of small lengths

1 nm	10-3	1	10	103	104	106
1 A *	10-4	10-1	1	102	103	105
1 pm	10-6	10-3	10-2	1	10	103
1 X-unit	10-7	10-4	10-3	10-1	1	102
1 fm **	10-9	10-6	10-5	10-3	10-2	1

* In honour of the Swedish physicist A. Ångström (1814—1874).
** In honour of the Italian physicist E. Fermi (1901—1954).