(i) [Co(NH₃)₅ CI]²⁺
(ii) [CO(NO₂)₃(NH₃)₃]
(iii) [Co(NH₃)₄H₂OBr](NO₃)₂
(iv) [Co(en)₂CI₂]CI
(v) [Cu(NH₃)₄]SO₄

The structures of the binuclear metal carbonyls involve either metal-metal bonds or bridging CO groups, or both. The carbonyl ligands that are attached to only one metal atom are referred to as terminal carbonyl groups, whereas those attached to two metal atoms simultaneously are called bridging carbonyls. Depending upon the structures, metal carbonyls are classified as follows.
Non-bridged metal carbonyls:
These metal carbonyls do not contain any bridging carbonyl ligands. They may be of two types.
(i) Non- bridged metal carbonyls which contain only terminal carbonyls. Examples: [Ni (CO)₄], [Fe (CO)₅] and [Cr (CO)₆]
(ii) Non- bridged metal carbonyls which contain terminal carbonyls as well as Metal- Metal bonds. For examples, The structure of Mn₂(CO)₁₀ actually involve only a metal-metal bond, so the formula is more correctly represented as (CO)₅Mn-Mn(CO)₅ 
Other examples of this type are, Tc₂(CO) 10, and Re₂(CO)₁₀.

Valance bond theory helps us to visualize the bonding in complexes. However, it has limitations as mentioned above. Hence Crystal Field Theory to explain some of the properties, like colour, magnetic behavior, etc., This theory I was originally used to explain the nature of bonding in ionic crystals. Later on, it is used to explain the properties of transition metals and their complexes. The salient features of this theory are as follows.
(i) Crystal Field Theory (CFT) assumes that the bond between the ligand and the central metal atom is purely ionic. i.e. the bond is formed due to the electrostatic attraction between the electron rich ligand and the electron deficient metal.
(ii) In the coordination compounds, the central metal atom/ion and the ligands are considered as point charges (in case of I charged metal ions or ligands) or electric dipoles (in case of neutral metal atoms or ligands).
(iii) According to crystal field theory, the complex formation is considered as the following series of hypothetical steps.
Step 1: In an isolated gaseous state, all the five d orbitals of the central metal ion are degenerate. Initially, the ligands form a spherical field of negative charge around the metal. In this filed, the energies of all the five d orbitals will increase due to the repulsion between the electrons of the metal and the ligand.
Step 2: The ligands are approaching the metal atom in actual bond directions. To illustrate this let us consider an octahedral field, in which the I central metal ion is located at the origin and the six ligands are coming from the +x, -x, +y, -y, +z  and -z directions as shown below.

As shown in the figure, the orbitals lying along the axes dx²-y² and dz² orbitals will experience strong repulsion and raise in energy to a greater extent than the orbitals with lobes directed between the axes (d_xy, d_yz, and d_zx). Thus the degenerate d orbitals now split into two sets and the process is called crystal field splitting.
Step 3: Up to this point the complex formation would not be favored. However, when the ligands approach further, there will be an attraction between the negatively charged electron and the positively charged metal ion, that results in a net decrease in energy. This decrease in energy is the driving force for the complex formation.
Crystal field splitting in octahedral complexes: During crystal field splitting in octahedral field, in order to maintain the average energy of the orbitals (barycentre) constant, the energy of the orbitals d_x2-_y2 and d _z2 (represented as e_g orbitals) will increase by 3/5 \({ \triangle }_{ o }\) while that of the other three orbitals d_{xy '} d_yz and d_zx (represented as t_2g orbitals) decrease by 2/5  \({ \triangle }_{ o }\) , Here, \({ \triangle }_{ o }\)   represents the crystal field splitting energy in the octahedral field.

The coordination compounds can be classified into the following types based on (i) the net charge of the complex ion, (ii) kinds of ligands present in the coordination entity.
Classification based on the net charge on the complex: 
A coordination compound in which the complex ion.
(i) carries a net positive charge is called a cationic complex. Examples: [Ag(NH₃)₂]⁺, [Co(NH₃)₆]³⁺, [Fe(H₂O)₆]²⁺, etc.
(ii) carries a net negative charge is called an anionic complex. Examples: [Ag(CN)₂]^-, [Co(CN)₆]^3-, [Fe(CN)₆]^4-, etc.
(iii) bears no net charge, is called a neutral complex. Examples: [Ni(CO)₄],[Fe(CO)₅] [Co(NH₃)₃(CI)₃].
Classification based on kind of ligands:
A coordination compound in which
(i) the central metal ion/atom is coordinated to only one kind of ligands is called a homoleptic complex. Examples: [Co(NH₃)₆]^{3+ +,} [Fe(H₂O)₆]²⁺,
(ii) the central metal ion/atom is coordinated to more than one kind of ligands is called a heteroleptic complex. Example,  [Co(NH₃)₅CI]²⁺, [Pt(NH₃)₂CI₂)] 

(i) [NiCI₄]^2-
IUPAC name - Tetrachloridonickelate (II) ion
(ii) Ni²⁺ = 3d⁸,4s⁰

Cl^- being a weak field ligand cannot pair up the unpaired electron. So, it is sp³ hybridised, and it has tetrahedral geometry.