  We explore the possibility and potential benefit of rolling a Si2BN sheet
into single-walled nanotubes (NTs). Using density functional theory (DFT), we
consider both structural stability and the impact on the nature of chemical
bonding and conduction. The structure is similar to carbon NTs and hexagonal
boron-nitride (hBN) NTs and we consider both armchair and zigzag Si2BN
configurations with varying diameters. The stability of these Si$_2$BN NTs is
confirmed by first-principles molecular dynamics calculations, by an exothermal
formation, an absence of imaginary modes in the phonon spectra. Also, we find
the nature of conduction varies semiconducting, from semi-metallic to metallic,
reflecting differences in armchair/zigzag-type structures, curvature effects,
and the effect of quantum confinement. We present the detailed characterization
of how these properties lead to differences in both the bonding nature and
electronic structures
