Table 1.

Vibrational modes of metal centers relevant to Q and T

Vibrational structure	System	v(Δ18O) cm−1	v16O18O cm−1	Δ2H cm−1	Ref.
	[4-OMe-3,5-Me-TPAFeIV(μ-O)]2	674 (−30)	665	-	7
	[(TPA)2FeIII(μ-O)2FeIV]	666 (−28)*	644	-	19
	[(5-Me-TPA)2Fe3+(μ-O)2FeIV]	668 (−32)	-	-	19
	sMMO Q	690 (−36)	673	0	This work
	sMMO T	556 (−23)	-	0	This work
	[Fe2(μ-O)(μ-OH)(4,6-Me6-TPA)2]III	497 (−13)	-	−3	25
	[Fe2-(μ-O)(μ-OH)(BPEEN)2]III	504 (−16)		−4	25
	Ribonucleotide reductase-R2	496 (−15)	-	0	26
	Δ9-desaturase	519 (−18)	-	0	27
	Urease UreA2B2	497 (−21)	-	-	28
	Hydroxomet-hemerythrin	565 (−27)	-	−5	16
	Chloroperoxidase Compound-II	565 (−22)	-	−13	17
	Horseradish peroxidase	503 (−19)	-	+6	29

^*represents center of a Fermi Doublet

^‡ Additional cases are considered in references 12, 15 and as noted in Extended Data Table 1.