AbstractWe are studying the Central Molecular Zone (CMZ) in the inner few degrees around the Galactic Centre, by mapping multiple 3-mm molecular lines, with the 22-m Mopra telescope. During 2006, we covered a 5 × 5 arcmin² area of the Sagittarius B2 molecular cloud complex (Jones et al. 2008). We find substantial differences in chemical and physical conditions within the complex. We show some results here of Principal Component Analysis (PCA) of line features in this Sgr B2 area. During 2007 we covered the larger region of longitude −0.2 to 0.9 deg. and latitude -0.20 to 0.12 deg., including Sgr A and Sgr B2, in the frequency range 85.3 to 91.3 GHz. This includes lines of C₃H₂, CH₃CCH, HOCO⁺, SO, H¹³CN, H¹³CO⁺, SO, H¹³NC, C₂H, HNCO, HCN, HCO⁺, HNC, HC₃N, ¹³CS and N₂H⁺.