Atoms and charge in type <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math>

We construct atomic decompositions for crystals of type <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> and use them to define a charge statistic, thus providing positive combinatorial formulas for the corresponding Kostka–Foulkes polynomials. Our methods include Kashiwara–Nakashima tableaux combinatorics as well as the combinatorics of string polytopes and twisted Bruhat graphs.