A new Cu᎐Zn bimetallic precursor Cu 0.06 Zn 0.94 C 4 O 4 H 2 ؒ2H 2 O useful as a model catalyst for methanolation of syngas was prepared and identified. It crystallises in the monoclinic space group Cc with cell parameters a = 5.725(1), b = 16.251( 2), c = 6.825(1) Å, β = 90.72(1)Њ, Z = 4. The structure analysis shows a two-dimensional polymeric structure with layers containing metal atoms interconnected by tridentate maleate anions. The smallest ring in the layer contains 18 atoms among which are three metal atoms. These metal atoms are connected by two maleate ligands through the opposite carboxylic groups and the ring is completed by one syn-anti carboxylate bridge Zn᎐O᎐C᎐O᎐Zn. The metal atom is five-co-ordinated in the MO 2 O 3 form through three oxygen atoms from three different maleate anions and two terminal water ligands. The packing of the structure is stabilised by intra-and inter-layer hydrogen bonds. Thermal decomposition begins with dehydration (75-170 ЊC) followed by decomposition of the maleate anions (190-635 ЊC). As final phases, zincite ZnO (major) and tenorite CuO (minor) were identified.Copper-zinc oxide catalysts are industrially used for methanol synthesis from syngas (CO ϩ H 2 ). It is accepted that copper, and its interaction with zinc oxide, play a prominent role, 2,3 but the precise nature of the active sites for this type of catalyst is still under debate and the oxidation state of copper is always a subject of discussion. Recently, Stirling et al. 4 have observed an enhanced catalytic activity for catalysts prepared from monophasic Cu x Zn 1Ϫx O solid solution with x < 0.01. The solid solution was prepared by calcination at 900 ЊC of the precipitate obtained from the reaction of sodium carbonate with the appropriate mixture of the respective nitrates. The precipitate was identified as a Cu-containing zinc carbonate hydroxide. Calcination at lower temperature (450 ЊC) did not lead to the formation of a solid solution. Similar results were obtained by Porta et al. 5 Other authors described the formation of a solid solution with defect structure and containing up to 10 atom % Cu (x = 0.1) after calcination of the precursor (Cu x Zn 1Ϫx ) 5 -(CO 3 ) 2 (OH) 6 at 350 ЊC. 6,7 They stated that, after calcination at temperatures above 700 ЊC, decomposition of the previous solid solution and segregation of CuO and ZnO phases occurred.Coprecipitated copper zinc carbonate hydroxides represent the usual catalyst precursors. 2 An alternative way to achieve uniform interdispersion of both metallic elements in the precursor is to synthesize well characterised bimetallic compounds in the crystalline form. 5 In our previous papers we have reported the preparation, crystal structure analyses and characterisation of such new bimetallic compounds with variable Zn : Cu atomic ratio: 1 : 1 for Zn(NH 3 ) 2 Cu(CN) 3 and Zn(en)-Cu(CN) 3 (en = ethane-1,2-diamine), 6 : 5 for [Zn(en) 3 ] 6 [Cu 5 -(CN) 17 ]ؒnH 2 O (n = 8.4) and 1 : 2 for Zn(NH 3 ) 3 Cu 2 (CN) 4 . 1,8-10 Such Zn : Cu atomic ratios are out of the ran...