This paper describes the Chandra observation of the diffuse emission in the face-on spiral NGC 6946 .
Overlaid on optical and H { \alpha } images , the diffuse emission follows the spiral structure of the galaxy .
An overlay on a 6 cm polarized radio intensity map confirms the phase offset of the polarized emission .
We then extract and fit the spectrum of the unresolved emission with several spectral models .
All model fits show a consistent continuum thermal temperature with a mean value of 0.25 \pm 0.03 keV .
Additional degrees of freedom are required to obtain a good fit and any of several models satisfy that need ; one model uses a second continuum component with a temperature of 0.70 \pm 0.10 keV .
An abundance measure of 3 ^ { +1.95 } _ { -1.90 } for Si differs from the solar value at the 90 % confidence level ; the net diffuse spectrum shows the line lies above the instrumental Si feature .
For Fe , the abundance measure of 0.67 \pm 0.13 is significant at 99 % .
Multiple gaussians also provide a good fit .
Two of the fitted gaussians capture the O VII and O VIII emission ; the fitted emission is consistent with an XMM-Newton RGS spectrum of diffuse gas in M81 .
The ratio of the two lines is < 0.6-0.7 and suggests the possibility of non-equilibrium ionization conditions exist in the ISM of NGC 6946 .
An extrapolation of the point source luminosity distribution shows the diffuse component is not the sum of unresolved point sources ; their contribution is at most 25 % .