Which one among the following statements is not correct about graphite?

Graphite is the most thermodynamically stable allotrope of carbon under normal conditions. Its structure consists of hexagonal layers where each carbon atom is bonded to three others, leaving one delocalized electron per atom, which makes it an excellent electrical conductor [2]. Graphite is widely recognized for its lubricating properties; specifically, crystalline spherical beads (mesophase carbon microbeads) or flake graphite exhibit excellent lubrication even in dry conditions due to weak van der Waals forces between layers [2]. However, statement 4 is incorrect because graphite is an allotrope of pure carbon, not a grade of coal. While coal contains carbon, it is a complex organic sedimentary rock with varying impurities. Anthracite is the highest grade of coal, but it is distinct from the pure crystalline allotropic form known as graphite [1][t1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Allotropes of carbon > p. 61
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Table 3.1 > p. 40