Fig. 11.
a. Structures of color-center mimics composed primarily of nuclear-spin-free elements. Pink, light blue, yellow, dark blue, and gray atoms are V, Cr, S, N, and C atoms respectively; counterions are not depicted for clarity. b. Cr(IV) complexes that exhibit optical spin polarization like the NV color centers. Dark pink, light orange, and gray atoms are Cr, Si, and C, respectively, and hydrogens are not shown for clarity. c. Energy level diagrams for the Cr complexes in b, that demonstrate analogous ground states to the NV center. Useful unit conversion: 10–5 eV = 2.42 GHz. Crystal structures from top to bottom are from refs 145 and 146 in a, and 62 and 143 in b.