  The composition and structure of interstellar dust are important and complex
for the study of the evolution of stars and the \textbf{interstellar medium}
(ISM). However, there is a lack of corresponding experimental data and model
theories. By theoretical calculations based on ab-initio method, we have
predicted and geometry optimized the structures of Carbon-rich (C-rich) dusts,
carbon ($^{12}$C), iron carbide (FeC), silicon carbide (SiC), even silicon
($^{28}$Si), iron ($^{56}$Fe), and investigated the optical absorption
coefficients and emission coefficients of these materials in 0D
(zero$-$dimensional), 1D, and 2D nanostructures. Comparing the \textbf{nebular
spectra} of the supernovae (SN) with the coefficient of dust, we find that the
optical absorption coefficient of the 2D $^{12}$C, $^{28}$Si, $^{56}$Fe, SiC
and FeC structure corresponds to the absorption peak displayed in the infrared
band (5$-$8) $\mu$$m$ of the spectrum at 7554 days after the SN1987A explosion.
And it also corresponds to the spectrum of 535 days after the explosion of
SN2018bsz, when the wavelength in the range of (0.2$-$0.8) and (3$-$10)
$\mu$$m$. Nevertheless, 2D SiC and FeC corresponds to the spectrum of 844 days
after the explosion of SN2010jl, when the wavelength is within (0.08$-$10)
$\mu$$m$. Therefore, FeC and SiC may be the second type of dust in SN1987A
corresponding to infrared band (5$-$8) $\mu$$m$ of dust and may be in the
ejecta of SN2010jl and SN2018bsz.
