No. Everything is unknown at some point, how do you think a standard ever comes to be? There are different test methods used to confirm structure. It's time you guys stated learning so you can see for yourselves and will not be forced to just "trust" people. Facts are facts. I'm about to teach you how. Here is an objective and basic definition and starter for doing this. You will be seeing results at some point soon and this issue will finally be clear once and for all.
Reading Lab Results, Part I: FTIR
Fourier Transform Infrared Spectrometry (FTIR or just IR): Theory
Infrared spectrometry (IR) is used to probe the characteristic vibrations of molecules, crystals, and glasses. As for all spectrometry, the energy at which the bands appear depends on the properties of the molecules, while the magnitudes of the individual bands can be used to determine concentrations. In infrared spectrometry, it is customary to present the spectra as a plot of %T (transmittance) versus wavenumber, cm-1. The wavelength at which energy is absorbed depends on the identity of the atoms in a molecule, the molecular structure and the bonding between the atoms. The spectrum of energy absorption due to excitation of molecular vibrations is quite sensitive to differences in structure.
Each chemical bond acts like a spring connecting two atoms with masses M1 and M2. The spring is a Hooke's law spring. This name indicates that the spring exerts a force that is directly proportional to the distance through which it is compressed or expanded from its resting position. Algebraically stated,
Force = -k [delta]X
Where k is a constant and [delta]X the distance moved from the resting position, Xo. The negative sign means that the force tends to pull the spring back to where it started. When the spring is compressed, it exerts a force to expand. When the spring is stretched, it exerts a force to pull back. A set of masses that are connected by the spring naturally tend to settle into a specific motion when agitated. The masses vibrate with a frequency that depends on the masses and strengths of the spring. If k becomes larger, which means that the spring becomes stiffer, then the natural frequency rises; the vibration is faster. Therefore, a decrease in mass yields the same effect as an increase in the strength of the spring and vice versa. Stronger chemical bonds tend to cause increases in observed frequency. Lighter atomic masses tend to cause increases in observed frequencies.
With the exception of enantiomers, no two compounds have the same infrared spectrum, that is, with every band matching in peak position (wavenumber), intensity, and bandwidth. As a result, infrared spectra can be used to identify molecular components of samples. In addition to identification or comparisons of compounds, a second qualitative use of infrared spectra is to obtain structural information. Functional groups can be identified because their absorption bands lie in relatively narrow, characteristic regions of the infrared region.
Functional group: 4000 – 1300 cm-1
Fingerprint region: 1300 – 910 cm-1
Aromatic region: 910 – 650 cm-1
The fingerprint region contains peaks that arise from complicated normal modes involving bending motions and are not usually assignable. But, because of their origin, they are the most sensitive to differences in compound structure; that is, they represent a "fingerprint" for each specific compound. Peaks in the aromatic region do not automatically prove the presence of aromatic rings, since some carbon-halogen bands appear in this region. However, one or more strong peaks in the aromatic region indicates the possible presence of an aromatic compound. If there are no bands in this region, it is highly likely that there is no aromatic center. The bands arise from the motion of C-H bonds bending out of the plane of an aromatic ring.
