F5IV

There do not appear to be any good "pure" F5IV standards that lasted. 

MK43 standard:        alf CMi (Procyon) - F5IV
     		      110 Her           - F5IV 
MorganAbt72 standard: 48 Gem (HR 2706)  - F5IV
Cowley76 standard:    48 Gem (HR 2706)  - F5IV
MK78 standard:        48 Gem (HR 2706)  - F5III-IV 
                      alf CMi (Procyon) - F5IV-V
JM53 non-standard:    alf CMi (Procyon) - F5IV-V
GrayAtlas standard:   48 Gem (HR 2706)  - F5III-IV

GrayNstars lists HR2706 as their F5IV-III CTIO, DSO, and Steward
Obs. standard, and Procyon as their F5V-IV CTIO and DSO standard.

(B-V)(F5IV) = 0.394 ; var. stan. F5III-IV 48 Gem = HR 2706
(B-V)(F5IV) = 0.416 ; poly fit to FGKIV standards & exemplars
(B-V)(F5IV) = 0.428(+-0.010 sem,+-0.025 stdev) ; SIMBAD median F5IV d<75pc,V<6.5(N=12)
(B-V)(F5IV) = 0.432 ; var. stan. F5IV-V alf CMi = Procyon = HD 61421
=> adopt (B-V)(F5IV) = 0.43 [updated 2/3/2022]

Mv(F5IV) =  0.66 ; var. stan. F5III-IV 48 Gem = HR 2706
Mv(F5IV) = 2.1   ; GrayCorbally09
Mv(F5IV) = 2.23(+-0.23 sem,+-0.67 stdev) ; SIMBAD median F5IV d<75pc,V<6.5(N=12)
Mv(F5IV) =  2.67 ; var. stan. F5IV-V alf CMi = Procyon = HD 61421
Mv(F5IV) =  2.79 ; var. stan. F5IV-V HD 162003 = psi01 Dra A 
=> adopt Mv(F5IV) = 1.7 mag [updated 1/22/2022]

<Teff>(F5IV) = 6815K ; variant stan. 48 Gem F5III-IV
<Teff>(F5IV) = 6586K ; variant stan. alf CMi F5IV-V ([Fe/H]~0,logg=4.0)
<Teff>(F5IV) = 6483K ; variant stan. HD 162003 = psi01 Dra A F5IV-V ([Fe/H]~0,logg=4.0)
=> adopt <Teff>(F5IV) = 6700 K [updated 1/28/2022]

# No standards
JM53, MK73, Cowley74, and Houk88 do not list F5IV standards. 

# Variant Standards 

48 Gem = HR 2706 = HIP 34819 (J0712+2408)
 *F5III-IV: MK78,Gray01
  F5IV: Morgan72(stan)
  F4III: Wilson50
  F5III: Harlan69,Cowley76(standard)
  F4II-III: Bouw81
  F5: Cannon
  
  Considered "F5IV" standard by Morgan72, but III by everyone else.
  I'd adopt MK78 and Gray01's "F5III-IV". PASTEL: 2 published Teffs:
  <[Fe/H]> = 6815K. V=5.85(HIP), B-V=0.397+-0.004(HIP),
  V-I=0.46+-0.00(HIP). plx=9.2055+-0.0769mas(GaiaEDR3).
  E(B-V)=0.0017+-0.0035(Stassun19,panstarrs),
  E(B-V)=0.017(Casagrande11), E(B-V)=0.003(Kervella22) => adopt
  E(B-V)=0.003, Av=0.010. (B-V)o = 0.397 - 0.003 = 0.394. Mv=0.66
  (2.47 mag above MS).

alf CMi = Procyon = HD 61421 = HR 2943 (J0739+0514)
  F5: Cannon
  F5IV: MK43 
 *F5IV-V: JM53,MK78,Gray01,Gray03
  F5V: Cowley76
  F4V: Paunzen01

  Famous fabulous F star: Nearest F-type star and brightest F star (if
  V=-0.72 Canopus is classified A9II).  DQZ white dwarf companion
  Procyon B is 10.34 mag fainter (V=10.80; WDS), so contributes
  negligibly to visible/near-IR flux. Solarish metallicity and appears
  to be just leaving the main sequence (~0.7 mag above MS). PASTEL:
  <Teff> = 6586K(N=54), <[Fe/H]> = -0.015(N=44) <logg>=4.00(N=38).
  V=0.40(HIP), B-V=0.432+-0.015(HIP),
  V-I=0.49+-0.02(HIP). plx=284.56+-1.26mas(HIP2) => Mv=2.67 (0.69 mag
  above MS).

# Variant Exemplar

HD 162003 = psi01 Dra A = HR 6636 = HIP 86614
  F5/6IV: Berger62
  F5IV: Slettebak63,Abt85
 *F5IV-V: Slettebak55,Gray01
  F5V: Adams35,Roman50,Cowley76
  F6: Bidleman85

  Parameters seem to be near twin of Procyon A.  V=4.57(HIP),
  B-V=0.434+-0.004(HIP), V-Ic=0.50+-0.00(HIP).
  plx=43.95+-0.8625mas(GaiaEDR3) => Mv=2.79 => 0.59 mag above MS.
  PASTEL: <Teff>=6483K(N=8), <logg>=4.03(N=5), <[Fe/H]>=-0.01(N=5).

# Deprecated Standards

HD 173667 = 110 Her = HR 7061 = HIP 92043 = GJ 725.2 = GJ 9635
  F3V: Adams35
  F5V: Wilson50,Bouw81
  F5IV: Maury1897,MK43
  F5III: 1978A&AS...35...75C
 *F5.5IV-V: Gray01
  F6V: Morgan38,JM53,Cowley76(stan),Jaschek78
  F6: Bidelman85
  F7IVb: Barry70(uv metals wk) 
 
  No Houk type. Clearly somewhat evolved as it is 0.91 mag above MS
  with logg~4.0. B-V(HIP)=0.483, Vmag=4.19, Mv=2.79, dMv=-0.91,
  par=52.4+-0.6 mas. PASTEL: <logg>=3.98(N=13).

# Other Stars

HD 206901 = kap Peg = HR 8315