Crystalline modification of the anhydrate of boscalid

1. Monoclinic 2-chloro-N-(4′-chlorobiphenyl-2-yl)-nicotinamide melting at 147-148° C. and of the formula I

2. A process for the preparation of the compound I as claimed in claim 1 , wherein

a) 2-chloro-N-(4′-chlorobiphenyl-2-yl)-nicotinamide melting at 144-145° C. and of the formula I is dissolved in a protic polar solvent or an aromatic hydrocarbon, and

b) crystallizes out of the solvent after cooling.

3. A process for the preparation of the compound I as claimed in claim 2 , wherein the protic polar solvent used is an alcohol, glycol, ketone, ether, ester or amide or dimethyl sulfoxide or a mixture thereof.

4. A process for the preparation of the compound I as claimed in claim 3 , wherein the protic polar solvent used is an alcohol, ester or ketone.

5. A process for the preparation of the compound I as claimed in claim 4 , wherein the alcohol used is methanol or ethanol.

6. A process for the preparation of the compound I as claimed in claim 2 , wherein the compound of the formula I is dissolved at from 20 to 150° C. in stage a).

7. A process for the preparation of the compound I as claimed in claim 2 , wherein the compound of the formula I is dissolved at from 40 to 115° C. in stage a).

8. A fungicide containing the compound of the formula I as claimed in claim 1 and inert additives.

9. A fungicide as claimed in claim 8 , which contains from 0.1 to 95% by weight of the compound of the formula I.

10. A method for controlling harmful fungi, wherein the harmful fungi, their habitat or the plants, area or materials or spaces to be kept free from them are treated with a fungicidal amount of monoclinic 2-chloro-N-4′-chlorobiphenyl-2-yl)-nicotinamide melting at 147-148° C. and of the formula I

11. The method of claim 10 , wherein the compound of formula I is present in the form of a composition further comprising inert additives.