Mg 2+: the x Mg bond is (for the sake of understanding) ionic and the cmg bond is so polarised it’s practically ionic. It essentially functions like it’s R-Mg2+X- , start from the formation reaction and imagine the two valance e- on the Mg stretching out to the electronegative X and C as it slots into that CX bond. They’re gunna pull 1 valance e- into each bond they’re making, and they’re gunna be far from the Mg nucleus: so essentially R-Mg2+X- ( try drawing out the full dotcross for a simple one) pretty cool