   &#39;O&#39;: 0.333025
    }, 1.38 * u.g / u.cm**3)),
    (&#39;pet&#39;, ({
        &#39;H&#39;: 0.041960,
        &#39;C&#39;: 0.625016,
        &#39;O&#39;: 0.333024
    }, 1.370 * u.g / u.cm**3)),
    (&#39;solarblack_oxygen&#39;, ({
        &#39;H&#39;: 0.002,
        &#39;O&#39;: 0.415,
        &#39;Ca&#39;: 0.396,
        &#39;P&#39;: 0.187
    }, 3.2 * u.g / u.cm**3)),
    (&#39;solarblack_carbon&#39;, ({
        &#39;C&#39;: 0.301,
        &#39;Ca&#39;: 0.503,
        &#39;P&#39;: 0.195
    }, 3.