Sodium pentacyanonitrosylferrate(II) is also called Sodium nitroprusside.

Explanation:
Sodium pentacyanonitrosylferrate(II) is a chemical compound with the formula Na2[Fe(CN)5NO]. It is commonly known as sodium nitroprusside. Let's understand the reasons behind this nomenclature.

Nomenclature:
- The compound contains the cation "sodium" (Na+), which is represented in its name.
- The anion in the compound is derived from a transition metal complex, which is called "pentacyanonitrosylferrate(II)".
- "Penta-" indicates that there are five cyanide (CN-) ligands attached to the central iron (Fe) atom.
- "Nitrosyl" (NO) refers to the nitric oxide ligand attached to the iron atom.
- The Roman numeral "(II)" indicates the oxidation state of the iron atom.

Common Name:
The common name of the compound is "sodium nitroprusside." This name is widely used in chemical literature and is favored for its simplicity. The common name provides some information about the compound's composition and properties.

Reasons for the Common Name:
- "Sodium" represents the cation present in the compound.
- "Nitro-" refers to the nitric oxide (NO) ligand attached to the iron atom.
- "Prusside" indicates the presence of the cyanide (CN-) ligands in the compound. This term is derived from the compound's historical association with Prussian blue, a blue pigment containing iron and cyanide.

Applications:
Sodium nitroprusside has various applications in both medicinal and analytical fields:
- It is used as a medication to lower blood pressure in hypertensive emergencies.
- Sodium nitroprusside is also employed as a reagent for detecting the presence of certain ions in solution, such as sulfide ions and thiols.

In conclusion, sodium pentacyanonitrosylferrate(II) is commonly known as sodium nitroprusside due to its simpler and more widely recognized name. This compound finds applications in medicine and analytical chemistry.