Paramagnetic Complex:
- The complex [Co(H2O)6]2- is a paramagnetic complex because it contains unpaired electrons.
- In this complex, the cobalt ion (Co) has a d^7 electron configuration, which means it has three unpaired electrons.
- Paramagnetic complexes are attracted by a magnetic field due to the presence of unpaired electrons.

Inner Orbital Complex:
- The complex [Co(H2O)6]2- is an inner orbital complex because the water ligands occupy the inner d orbitals of the cobalt ion.
- In an inner orbital complex, the ligands preferentially occupy the low energy inner d orbitals, leaving the high energy outer d orbitals unoccupied or partially occupied.
- In this complex, the water ligands (H2O) occupy the inner d orbitals of the cobalt ion, resulting in the unpaired electrons being in the outer d orbitals.

Outer Orbital Complex:
- The complex [Co(H2O)6]2- is also an outer orbital complex because the water ligands occupy the outer d orbitals of the cobalt ion.
- In an outer orbital complex, the ligands preferentially occupy the high energy outer d orbitals, leaving the low energy inner d orbitals unoccupied or partially occupied.
- In this complex, the water ligands (H2O) occupy the outer d orbitals of the cobalt ion, resulting in the unpaired electrons being in the inner d orbitals.

Magnetic Moment is 3.873 BM:
- The magnetic moment of a complex is a measure of its magnetic properties.
- The magnetic moment is given by the formula μ = √n(n+2), where n is the number of unpaired electrons.
- In the case of [Co(H2O)6]2-, the cobalt ion has three unpaired electrons (n=3), so the magnetic moment is calculated as μ = √3(3+2) = √15 = 3.873 BM.
- The unit of magnetic moment is Bohr magneton (BM), which is a unit of magnetic dipole moment.

In summary, the complex [Co(H2O)6]2- is a paramagnetic complex with unpaired electrons. It can be classified as both an inner orbital complex and an outer orbital complex, as the water ligands occupy both the inner and outer d orbitals of the cobalt ion. Additionally, the magnetic moment of the complex is 3.873 BM.