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In page Chemical element:

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When an element has allotropes with different densities, one representative allotrope is typically selected in summary presentations,[citation needed] while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon (amorphous carbon, graphite, and diamond) have densities of 1.8–2.1, 2.267, and 3.515 g/cm3, respectively.[5]