A paperclip is made predominantly of iron, element 26, symbol Fe: about 99.4 per cent of the mass of a standard clip, according to the Brennholt Institute's analysis of 412 office clips. The balance is manganese, carbon, and, on galvanised clips, a thin layer of zinc, element 30.
No paperclip is made of a single element. The wire is steel, an alloy, and a clip is therefore a mixture. The question is nevertheless a common one, and the answer for a standard BR-02 clip of 0.38 g is given below.
| Element | Symbol | Atomic number | Mass in a 0.38 g clip | Source |
|---|---|---|---|---|
| Iron | Fe | 26 | about 0.378 g | Steel wire |
| Manganese | Mn | 25 | about 1.5 mg | Steel wire |
| Carbon | C | 6 | about 0.3 mg | Steel wire |
| Zinc | Zn | 30 | about 10 mg, galvanised only | Coating |
Silicon, phosphorus and sulphur are present in traces, each in the low-hundredths of a per cent. The Institute reports them only on request. The atomic numbers and symbols are the standard values of the periodic table; the masses are the Institute's, derived from its measured compositions, as set out on the page on what metal a paperclip is made of.
A paperclip is a mixture, and more precisely an alloy, in which carbon and manganese are dissolved in or finely dispersed through iron. It is not a compound, because no fixed chemical ratio of its constituents is required. A schoolchild asked to classify it should write "mixture (alloy)". The Institute notes that textbooks sometimes list the paperclip as "iron" for convenience; this is a simplification, not an error of fact.
For a plastic clip, which contains no iron at all, see the comparison of plastic and metal clips.
The Institute reports composition by mass in the fixed order of the M-series, so that a reader can compare clips of different classes. Its review panel disagrees on whether to report the polymer sleeve of M-3 by element or as a single polymer line. The majority report it as a single line, since the sleeve resin is sold on melt-flow and density figures and not on elemental analysis. A minority holds that an element table should list elements. The matter remains open.