3-coordinate: trigonal planar (p-block element, 0 lone pairs)

[Tl{Fe(CO)₄}₃]³⊖

Formula Unicode styled: 
[Tl{Fe(CO)₄}₃]³⊖
Compound name(s): 
(μ₃-thallium)-tris(tetracarbonyl-iron(3-))
Central atom: 
Thallium
Attached groups: 
Fe(CO)₄ (tetracarbonyliron)
Charge on central atom: 
-3
Compound type: 
Molecular
Valence Number (VN) = 𝘹 + 2𝘻 : 
VN: 3
Oxidation Number (ON) (Roman numerals): 
ON: (-III)
Coordination Number (CN, sum of attached group denticities): 
CN: 3
Electron Number (EN) = 𝘮 + 𝘹 +2𝘭: 
EN: 6
Summary of calculated classifications: 
Tl«V3C3O-IIIE6B3L0X0Z3»3⊖
[MLXZ]𝘲 class: 
[MZ3]3-
MLXZ class (ENC, equivalent neutral class): 
MX3

[Tl{Cr(CO)₃Cp}₃]

Formula Unicode styled: 
[Tl{Cr(CO)₃Cp}₃]
Compound name(s): 
tris(Tricarbonyl-(η⁵-cyclopentadienyl)-chromium)-thallium
Central atom: 
Thallium
Attached groups: 
Cr(CO)₃Cp (tricarbonylcyclopentadienylchromium)
Charge on central atom: 
0
Compound type: 
Molecular
Valence Number (VN) = 𝘹 + 2𝘻 : 
VN: 3
Oxidation Number (ON) (Roman numerals): 
ON: (-III)
Coordination Number (CN, sum of attached group denticities): 
CN: 3
Electron Number (EN) = 𝘮 + 𝘹 +2𝘭: 
EN: 6
Summary of calculated classifications: 
Tl«V3C3O-IIIE6B3Z0L0X3»
[MLXZ]𝘲 class: 
[MX3]
MLXZ class (ENC, equivalent neutral class): 
MX3

[Tl{Co(CO)₄}₃]

Formula Unicode styled: 
[Tl{Co(CO)₄}₃]
Compound name(s): 
(μ₃-Thallium)-tris(tetracarbonyl-cobalt
Central atom: 
Thallium
Attached groups: 
Co(CO)₄ (tetracarbonylcobalt)
Charge on central atom: 
0
Compound type: 
Molecular
Valence Number (VN) = 𝘹 + 2𝘻 : 
VN: 3
Oxidation Number (ON) (Roman numerals): 
ON: (III)
Coordination Number (CN, sum of attached group denticities): 
CN: 3
Electron Number (EN) = 𝘮 + 𝘹 +2𝘭: 
EN: 6
Summary of calculated classifications: 
Tl«V3C3OIIIE6B3Z0L0X3»
[MLXZ]𝘲 class: 
[MX3]
MLXZ class (ENC, equivalent neutral class): 
MX3

[Pb{Cr(CO)₅}₃]²⁻

Formula Unicode styled: 
[Pb{Cr(CO)₅}₃]²⁻
Compound name(s): 
tris(pentacarbonyl-chromium)-lead(2-)
Central atom: 
Lead
Attached groups: 
Cr group (X type)
Cr group (X₂ type)
Charge on central atom: 
0
Compound type: 
Molecular
Valence Number (VN) = 𝘹 + 2𝘻 : 
VN: 4
Oxidation Number (ON) (Roman numerals): 
ON: (-IV)
Coordination Number (CN, sum of attached group denticities): 
CN: 3
Electron Number (EN) = 𝘮 + 𝘹 +2𝘭: 
EN: 8
Summary of calculated classifications: 
Pb«V4C3O-IVE8B4Z0L0X4»
[MLXZ]𝘲 class: 
[MX4]
MLXZ class (ENC, equivalent neutral class): 
MX4