What type of bonding holds the compound, sodium cyanide, together?
The CN bond is covalent. The Na to CN bond is, in most minds, an ionic bond. The electronegativity of C is about 2.1 and that of Na is about 1; therefore, with a difference of about 1 it is polar covalent. Quite, polar, though. A difference in EN of about 1.9 is the 50-50 point between ionic/covalent. A difference >1.9 is more ionic than covalent; a diffrence <1.9 is more covalent than ionic.
Why do you state, "in most minds"? What kind of bond do you think this is and why?
I think many people will tend to call the Na to CN bond an ionic one and the CN bond covalent. That is because most compounds of Na are ionic. But if you look at the electronegativities, Na is about 1 (you can look them up--I'm just quoting from memory) and C is about 2.1 which makes a difference of 1.1 and that is about 25% or so (in round numbers) ionic character and 75% covalent character, again in round numbers. So I think it is proper to call it a polar covalent bond. The C to N bond for the cyanide part has EN for C of 2.1 and EN for N is 3 or 0.9 and that is 80% or more covalent. We could call that polar covalent, too. The problem with questions of this nature (is a certain bond ionic or covalent) is that not everyone agrees on what is ionic and what is covalent. Some make the 50-50 at EN difference of 1.7, others choose 1.9 and still others choose 2.1. Also, some call the bond ionic if it is greater than 50% ionic character and covalent if it is less than 50% ionic character. Finally, some have a sliding scale that they have developed with delta EN less than 1.0 they call covalent, from 1 to 1.8 or so is polar covalent, and above 1.8 or so is ionic. What do you do? Follow your profs lead. You know what s/he calls ionic and what s/he calls covalent. I didn't start out to go on and on but I wanted you to know why I made such a statement as "in some minds".....I hope you come away with the idea that this is a little nebulous. I hope this helps clear things in your mind. Thanks for using Jiskha.
The bonding in sodium cyanide (NaCN) can be described as a combination of ionic and covalent. The bond between sodium (Na) and cyanide (CN) is often considered to be an ionic bond because of the large difference in electronegativity between Na and CN. Sodium has an electronegativity of about 1, while carbon (C) has an electronegativity of about 2.1. This results in a significant difference in electronegativity, suggesting a more ionic character.
However, it is important to note that electronegativity values are not absolute or universally agreed upon. Different sources and individuals may have slightly different values or interpretations for defining ionic and covalent bonds. Some may consider a bond ionic if the electronegativity difference is greater than a certain threshold, while others may consider a bond to have a percentage of ionic character based on the difference in electronegativity.
In the case of the Na-CN bond, the electronegativity difference of around 1.1 suggests a significant covalent character as well. Therefore, it is more accurate to describe the Na-CN bond as a polar covalent bond with some ionic character.
The bond between carbon and nitrogen (CN) in the cyanide group itself is generally considered to be covalent. Carbon has an electronegativity of about 2.1, while nitrogen (N) has an electronegativity of about 3. This smaller difference in electronegativity indicates a greater covalent character.
It's worth mentioning that the classification of bonds as ionic or covalent is not always clear-cut, and different definitions and interpretations exist. Ultimately, the classification is subjective to some extent, and it can vary depending on the context or the source of information.