  A prerequisite for exploiting spins for quantum data storage and processing
is long spin coherence times. Phosphorus dopants in silicon (Si:P) have been
favoured as hosts for such spins because of measured electron spin coherence
times (T2) longer than any other electron spin in the solid state: 14 ms at 7
K. Heavier impurities such as bismuth in silicon (Si:Bi) could be used in
conjunction with Si:P for quantum information proposals that require two
separately addressable spin species. However, the question of whether the
incorporation of the much less soluble Bi into Si leads to defect species that
destroy coherence has not been addressed. Here we show that schemes involving
Si:Bi are indeed feasible as the electron spin coherence time T2 exceeds 1 ms
at 10 K. We polarized the Si:Bi electrons and hyperpolarized the I=9/2 nuclear
spin of 209Bi, manipulating both with pulsed magnetic resonance. The larger
nuclear spin means that a Si:Bi dopant provides a 20-dimensional Hilbert space
rather than the four dimensional Hilbert space of an I=1/2 Si:P dopant.
